Photofeed

A photoflash capacitor is an electrolytic capacitor used in flash cameras, professional flashes, and also in solid-state laser power supplies. Their usual purpose is to briefly power a high-voltage flash tube, used to illuminate a photographic subject or optically pump a laser rod.

Photograph is the third album by Philippine singer, Ariel Rivera. The album was released three years after his second due to his acting career. It features the hits, "Narito Ako" and "I Must Have Loved You".

Photoelectric flame photometer

Photofragment ion imaging or, more generally, Product Imaging is an experimental technique for making measurements of the velocity of product molecules or particles following a chemical reaction or the photodissociation of a parent molecule. The method uses a two-dimensional detector, usually a microchannel plate, to record the arrival positions of state-selected ions created by resonantly enhanced multi-photon ionization (REMPI). The first experiment using photofragment ion imaging was performed by David W Chandler and Paul L Houston in 1987 on the phototodissociation dynamics of methyl iodide (iodomethane, CH3I).

Photograbber (original title Photomateurs) is an 18-minute French live action short film (with English subtitles) written and directed by Pascal Tosi.

Photocast

Photodermatitis, sometimes referred to as sun poisoning or photoallergy, is a form of allergic contact dermatitis in which the allergen must be activated by light to sensitize the allergic response, and to cause a rash or other systemic effects on subsequent exposure. The second and subsequent exposures produce photoallergic skin conditions which are often eczematous. It is distinct from sunburn.

Photosensors or photodetectors are sensors of light or other electromagnetic energy. A photo detector has a p–n junction that converts light photons into current. The absorbed photons make electron–hole pairs in the depletion region. Photodiodes and photo transistors are a few examples of photo detectors. Solar cells convert some of the light energy absorbed into electrical energy.

A photoelectric flame photometer is a device used in inorganic chemical analysis to determine the concentration of certain metal ions, among them sodium, potassium, lithium, and calcium. Group 1 and Group 2 metals are quite sensitive to Flame Photometry due to their low excitation energies.In principle, it is a controlled flame test with the intensity of the flame color quantified by photoelectric circuitry.

Photoblepharon palpebratus

Photographers' Gallery

Photocatalytic water splitting is an artificial photosynthesis process with photocatalysis in a photoelectrochemical cell used for the dissociation of water into its constituent parts, hydrogen (H2) and oxygen (O2), using either artificial or natural light. Theoretically, only solar energy (photons), water, and a catalyst are needed.

Photoelectron spectroscopy

Photodotis

Photographic archive Gerola is preserved by the Istituto Veneto di Scienze, Lettere ed Arti at Palazzo Loredan in Venice.

A photoflash battery is a specialized zinc-carbon battery optimized to provide a high electric current output for a short duration of time, such as required to fire a flashbulb. Service life for this battery in flashlight service was short, since flashlights required a lower but continuous long duration current.Photoflash cells were in production during the flashbulb era, and were slowly phased out as alkaline cells came into general usage. The photoflash cell was produced as a 1.5 volt size D and size C cell.The cathode (the material packed between the carbon rod and zinc shell) of a zinc-carbon cell is generally made of powdered carbon black (or acetylene black), manganese dioxide and electrolyte. The MnO2 to carbon ratios vary between 10:1 and 3:1 for general purpose cells. A 1:1 mixture was used for photoflash batteries. This allowed a high current output with intermittent use, perfect for photoflash use.These cells have reduced capacity compared to those with a higher content of MnO2.

Photographers/Aspen

Photochemotherapy

Photographed in New Zealand

A photocopier (also known as a copier or copy machine) is a machine that makes paper copies of documents and other visual images quickly and cheaply. Most current photocopiers use a technology called xerography, a dry process that uses electrostatic charges on a light-sensitive photoreceptor to first attract and then transfer toner particles (a powder) onto paper in the form of an image. Heat, pressure or a combination of both is then used to fuse the toner onto the paper. (Copiers can also use other technologies such as ink jet, but xerography is standard for office copying.) Earlier versions included the Gestetner stencil duplicator, invented by David Gestetner in 1881.Commercial xerographic office photocopying was introduced by Xerox in 1959, and it gradually replaced copies made by Verifax, Photostat, carbon paper, mimeograph machines, and other duplicating machines.Photocopying is widely used in the business, education, and government sectors. While there have been predictions that photocopiers will eventually become obsolete as information workers increase their use of digital document creation, storage and distribution, and rely less on distributing actual pieces of paper, as of 2015, photocopiers continue to be widely used. In the 2010s, there is a convergence in some high-end machines between the roles of a photocopier, a fax machine, a scanner, and a computer network-connected printer into a multi-function printer. Lower-end machines that can copy and print in color have increasingly dominated the home-office market as their prices fell steadily through 2017. Higher-end color photocopiers capable of handling heavy duty cycles and large-format printing remain a costlier specialty for print and design shops.

Since its inception, the Photographic Society of Japan has annually presented a large number of awards.

Photoflamingo

Photoflash battery

Photodermatology, Photoimmunology and Photomedicine

Photografting is a technique used in the study of polymers and more in specific polymeric biomaterials. Technically speaking it is the covalent incorporation of functional additives to a polymer matrix or polymer surface using a light-induced mechanism. It is an important technique for the modification of biomaterial surfaces.

Photographers

Photocomposing

Photodotis palens is a moth of the Gelechiidae family. It was described by Omelko in 1993. It is found in the Russian Far East (Primorskii krai), Korea and Japan.The wingspan is about 11 mm.

Photochemical internalization (PCI) is a drug and gene therapy delivery method originally developed to improve the release of macromolecules and hydrophilic chemotherapeutic agents from endosomes and lysosomes to the cytosol of targeted cancer cells. PCI is based on the use of endosomal and lysosomal localizing amphiphilic photosensitizers which, after activation by light, induce photochemical reactions resulting in destruction of endocytic membranes mediated by reactive oxygen species (ROS). The photochemical destabilization of the membrane of the endocytic vesicle result in an endosomal escape of the entrapped drugs. The technology was invented by Professor Kristian Berg at the Norwegian Radium Hospital.

Photoeffect

Photoemission electron microscopy

Photographic Society of Great Britain

The Photochemical Reflectance Index (PRI) is a reflectance measurement developed by John Gamon during his tenure as a postdoctorate fellow supervised by Christopher Field at the Carnegie Institution for Science at Stanford University. The PRI is sensitive to changes in carotenoid pigments (e.g. xanthophyll pigments) in live foliage. Carotenoid pigments are indicative of photosynthetic light use efficiency, or the rate of carbon dioxide uptake by foliage per unit energy absorbed. As such, it is used in studies of vegetation productivity and stress. Because the PRI measures plant responses to stress, it can be used to assess general ecosystem health using satellite data or other forms of remote sensing. Applications include vegetation health in evergreen shrublands, forests, and agricultural crops prior to senescence. PRI is defined by the following equation using reflectance (ρ) at 531 and 570 nm wavelength: P R I = ( ρ 531 − ρ 570 ) ( ρ 531 + ρ 570 ) {\displaystyle PRI={\frac {(\rho 531-\rho 570)}{(\rho 531+\rho 570)}}} Some authors use P R I = ( ρ 570 − ρ 531 ) ( ρ 570 + ρ 531 ) {\displaystyle PRI={\frac {(\rho 570-\rho 531)}{(\rho 570+\rho 531)}}} The values range from –1 to 1.

Photoelectric relay

Photodermatology, Photoimmunology and Photomedicine is a peer-reviewed scientific journal published bimonthly by Wiley-Blackwell which focusses, as its title implies, on photodermatology, photoimmunology and photomedicine. Warwick L. Morison is editor-in-chief. It is the official journal of the Photomedicine Society, the British Photodermatology Group, and the European Society for Photodermatology.

Photodynamic cancer treatment

Photodetection

Photographic Convention of the United Kingdom

Photograph preservation

Photocopy

Photochemical carbon dioxide reduction

Photodotis abachausi is a moth of the Gelechiidae family. It was described by Janse in 1958. It is found in South Africa.

Photochemical reaction

Photodisintegration Hypernovae

Photograph Smile

A subject (generally a person) is photogenic if appearing aesthetically or physically attractive or appealing in photographs. Photogenic drawing, coined by William Fox Talbot, also describes the earliest method for recording images. Derives from Greek https://el.m.wiktionary.org/wiki/φωτογενής

A photograph conservator is a professional who examines, documents, researches, and treats photographs, including documenting the structure and condition of art works through written and photographic records, monitoring conditions of works in storage and exhibition and transit environments. This person also performs all aspects of the treatment of photographs and related artworks with adherence to the Code of Ethics outlined by the American Institute for Conservation.

Photoelectrochemical processes are processes in photoelectrochemistry; they usually involve transforming light into other forms of energy. These processes apply to photochemistry, optically pumped lasers, sensitized solar cells, luminescence, and photochromism.

A photocopier (also known as a copier or copy machine) is a machine that makes paper copies of documents and other visual images quickly and cheaply. Most current photocopiers use a technology called xerography, a dry process that uses electrostatic charges on a light-sensitive photoreceptor to first attract and then transfer toner particles (a powder) onto paper in the form of an image. Heat, pressure or a combination of both is then used to fuse the toner onto the paper.

Photoflash

Photocopyed

Photoemission

Photochrome

Photoelectrochemical cells or PECs are solar cells that produce electrical energy or hydrogen in a process similar to the electrolysis of water.

Photographic Memory (film)

Photocopies

Photographic interpretation

Photodrama of Creation

Photochromogenic

Photoelectric barrier

Photodotis abachausi

Photographic editorial

Photoconductive polymers

Photoelastic Effect

Photodissociation regions (or photon-dominated regions, or PDRs) are predominantly neutral regions of the interstellar medium in which far ultraviolet photons strongly influence the gas chemistry and act as the most important source of heat. They occur in any region of interstellar gas that is dense and cold enough to remain neutral, but that has too low a column density to prevent the penetration of far-UV photons from distant, massive stars.

A photoelectric flame photometer is a device used in inorganic chemical analysis to determine the concentration of certain metal ions, among them sodium, potassium, lithium, and calcium. Group 1 and Group 2 metals are quite sensitive to Flame Photometry due to their low excitation energies.In principle, it is a controlled flame test with the intensity of the flame color quantified by photoelectric circuitry. The intensity of the colour will depend on the energy that had been absorbed by the atoms that was sufficient to vaporise them. The sample is introduced to the flame at a constant rate. Filters select which colours the photometer detects and exclude the influence of other ions. Before use, the device requires calibration with a series of standard solutions of the ion to be tested.Flame photometry is crude but cheap compared to flame emission spectroscopy or ICP-AES, where the emitted light is analysed with a monochromator. Its status is similar to that of the colorimeter (which uses filters) compared to the spectrophotometer (which uses a monochromator). It also has the range of metals that could be analysed and the limit of detection are also considered

Photochrom (Fotochrom, Photochrome or the Aäc process) is a process for producing colorized images from black-and-white photographic negatives via the direct photographic transfer of a negative onto lithographic printing plates. The process is a photographic variant of chromolithography (color lithography).

Photocrime is an American television crime drama that was broadcast on ABC from September 28, 1949, until December 14, 1949. The program was also known as Look Photocrime.The program's title and premise -- "that photographs often possess clues that are often overlooked" initially -- came from an illustrated fictional crime series that ran in Look magazine, and the program was produced in association with Look.

A photocatalyst activity indicator ink (Paii) is a substance used to identify the presence of an underlying heterogeneous photocatalyst and to measure its activity. Such inks render visible the activity of photocatalytic coatings applied to various "self-cleaning" products. The inks contain a dyestuff that reacts to ultraviolet radiation in the presence of the photocatalytic agent in the coating. They are applied to the coated product using a pen or brush, and show a color change or disappearance when exposed to ultraviolet.

Photograph (album)

Photogram

Photographic flash

Photographic Speed Reading

Photodisruption

Photofont

Photochemical logic gate

Photoelectrochemical

Photographic Hypersensitization

Photochromic lenses are optical lenses that darken on exposure to specific types of light of sufficient intensity, most commonly ultraviolet (UV) radiation. In the absence of activating light the lenses return to their clear state. Photochromic lenses may be made of glass, polycarbonate, or another plastic. They are principally used in eyeglasses that are dark in bright sunlight, but clear in low ambient light conditions. They darken significantly within about a minute of exposure to bright light, and take somewhat longer to clear. A range of clear and dark transmittances are available.In one sort of technology, molecules of silver chloride or another silver halide are embedded in photochromatic lenses. They are transparent to visible light without significant ultraviolet component, which is normal for artificial lighting. In another sort of technology, organic photochromic molecules, when exposed to ultraviolet (UV) rays as in direct sunlight, undergo a chemical process that causes them to change shape and absorb a significant percentage of the visible light, i.e., they darken. These processes are reversible; once the lens is removed from strong sources of UV rays the photochromic compounds return to their transparent state

Photoconductivity is an optical and electrical phenomenon in which a material becomes more electrically conductive due to the absorption of electromagnetic radiation such as visible light, ultraviolet light, infrared light, or gamma radiation.When light is absorbed by a material such as a semiconductor, the number of free electrons and electron holes increases and raises its electrical conductivity.

Photodermatology

Photograph of Ieshia Evans

Photochemical reactions

Photoelectric work function

Photograph

Photoelectric effect equation

Photocure

Photoflamingo is the fifth studio album by Crack the Sky. It was released on LP in 1981 by Lifesong Records (catalog #LS-8133).

Photographic Memory is a 2011 documentary film by independent filmmaker Ross McElwee about a voyage back to the roots of his involvement with the camera.Photographic Memory premiered at the 2011 Venice Film Festival and won the Sheffield Youth Jury Award at Sheffield Doc/Fest in June 2012.

Photodetector

Photochemistry and Photobiology is a peer-reviewed scientific journal that publishes original research papers, rapid communications, research notes, technical notes, invited articles, and reviews covering photochemistry and photobiology.

Photodisintegration hypernovae

Photoelectric

Photoengraving is a process that uses a light-sensitive photoresist applied to the surface to be engraved to create a mask that shields some areas during a subsequent operation which etches, dissolves, or otherwise removes some or all of the material from the unshielded areas. Normally applied to metal, it can also be used on glass, plastic and other materials.A photoresist is selected which is resistant to the particular acid or other etching compound to be used. It may be a liquid applied by brushing, spraying, pouring or other means and then allowed to set, or it may come in sheet form and be applied by laminating. It is then exposed to light—usually strong ultraviolet (UV) light—through a photographic, mechanically printed, or manually created image or pattern on transparent film. Alternatively, a lens may be used to project an image directly onto it. Typically, the photoresist is hardened where it receives sufficient exposure to light, but some photoresists are initially hard and are then softened by exposure. A solvent is used to wash away the soft parts, laying bare the underlying material, which is then bathed in or sprayed with the acid or other etchant. The remaining photoresist is usually removed after the operation is complete.In the graphic arts, photoengraving is used to make printing plates for various printing processes, reproducing a wide variety of graphics such as lettering, line drawings and photographs.The same procedure is used to make printed circuit boards, foil-stamping dies and embossing dies. It is also used to make nameplates, commemorative plaques and other decorative engravings. It can be used to make flat springs, levers, gears and other practical components that would otherwise be fabricated from sheet metal by cutting, drilling, jigsawing or stamping. A very high degree of precision is possible. In these applications, it is properly called photochemical machining, but the terms photochemical milling, chemical milling and photoetching are sometimes used. A similar process called photolithography is used to make integrated circuits.

A photocathode is a negatively charged electrode in a light detection device such as a photomultiplier or phototube that is coated with a photosensitive compound. When this is struck by a quantum of light (photon), the absorbed energy causes electron emission due to the photoelectric effect.

Photogenin

Photochemical internalization (PCI) is a drug and gene therapy delivery method originally developed to improve the release of macromolecules and hydrophilic chemotherapeutic agents from endosomes and lysosomes to the cytosol of targeted cancer cells. PCI is based on the use of endosomal and lysosomal localizing amphiphilic photosensitizers which, after activation by light, induce photochemical reactions resulting in destruction of endocytic membranes mediated by reactive oxygen species (ROS).

A photocarcinogen is a substance which causes cancer following illumination. This destructive effect often results from free radicals generated by the photocarcinogen. Many chemicals that are not carcinogenic can be photocarcinogenic. This can easily be understood from a photochemical perspective: The reactivity of a chemical substance itself might be low, but after illumination it transfers to the excited state.

Photodermatoses is a skin disease that is caused by exposure to sunlight.People with photodermatoses may develop skin rashes following exposure to the sun. Polymorphous light eruption is the most common type of photodermatoses. It is most likely due to an abnormal immune system reaction to the sun. Polymorphous light eruption occurs in approximately 10 to 20 percent of otherwise healthy individuals, so it is a relatively common condition.

Photochem Photobiol

Photograph stability

A photogram is a photographic image made without a camera by placing objects directly onto the surface of a light-sensitive material such as photographic paper and then exposing it to light. The usual result is a negative shadow image that shows variations in tone that depends upon the transparency of the objects used.

Photoframe

Photocopy (film)

In photography and videography, a filter is a camera accessory consisting of an optical filter that can be inserted into the optical path. The filter can be of a square or oblong shape and mounted in a holder accessory, or, more commonly, a glass or plastic disk in a metal or plastic ring frame, which can be screwed into the front of or clipped onto the camera lens.Filters modify the images recorded. Sometimes they are used to make only subtle changes to images; other times the image would simply not be possible without them. In monochrome photography, coloured filters affect the relative brightness of different colours; red lipstick may be rendered as anything from almost white to almost black with different filters. Others change the colour balance of images, so that photographs under incandescent lighting show colours as they are perceived, rather than with a reddish tinge. There are filters that distort the image in a desired way, diffusing an otherwise sharp image, adding a starry effect, etc. Linear and circular polarising filters reduce oblique reflections from non-metallic surfaces.Many filters absorb part of the light available, necessitating longer exposure. As the filter is in the optical path, any imperfections—non-flat or non-parallel surfaces, reflections (minimised by optical coating), scratches, dirt—affect the image.There is no universal standard naming system for filters. The Wratten numbers adopted in the early twentieth century by Kodak, then a dominant force in film photography, are used by several manufacturers. Colour correction filters are often identified by a code of the form CC50Y—CC for colour correction, 50 for the strength of the filter, Y for yellow.Optical filters are used in various areas of science, including in particular astronomy; they are essentially the same as photographic filters, but in practice often need far more accurately controlled optical properties and precisely defined transmission curves than filters exclusively for photographic use. Photographic filters sell in larger quantities at correspondingly lower prices than many laboratory filters. The article on optical filters has material relevant to photographic filters.In digital photography the majority of filters used with film cameras have been rendered redundant by digital filters applied either in-camera or during post processing. Exceptions include the ultraviolet (UV) filter typically used to protect the front surface of the lens, the neutral density (ND) filter, the polarising filter and the infra red (IR) filter. The neutral density filter permits effects requiring wide apertures or long exposures to be applied to brightly lit scenes, while the graduated neutral density filter is useful in situations where the scene's dynamic range exceeds the capability of the sensor. Not using optical filters in front of the lens has the advantage of avoiding the reduction of image quality caused by the presence of an extra optical element in the light path and may be necessary to avoid vignetting when using wide-angle lenses.

Photoconductive atomic force microscopy (PC-AFM) is a variant of atomic force microscopy that measures photoconductivity in addition to surface forces.

Photodotis pellochroa is a moth of the Gelechiidae family. It was described by Janse in 1960. It is found in South Africa.

Photoelectrochemical processes

Photodermatosis

Photographic Horizons

Photoglo (Jim Photoglo album)

Photodynamic Therapy

In his historic paper entitled "The Quantum Theory of Optical Coherence," Roy J. Glauber set a solid foundation for the quantum electronics/quantum optics enterprise. The experimental development of the optical maser and later laser at that time had made the classical concept of optical coherence inadequate. Glauber started from the quantum theory of light detection by considering the process of photoionization in which a photodetector is triggered by an ionizing absorption of a photon. In the quantum theory of radiation, the electric field operator in the Coulomb gauge may be written as the sum of positive and negative frequency parts E ( r , t ) = E ( + ) ( r , t ) + E ( − ) ( r , t ) {\displaystyle E(\mathbf {r} ,t)=E^{(+)}(\mathbf {r} ,t)+E^{(-)}(\mathbf {r} ,t)} where E ( − ) ( r , t ) = E ( + ) ( r , t ) † {\displaystyle E^{(-)}(\mathbf {r} ,t)=E^{(+)}(\mathbf {r} ,t)^{\dagger }} One may expand E ( + ) ( r , t ) {\displaystyle E^{(+)}(\mathbf {r} ,t)} in terms of the normal modes as follows: E ( + ) ( r , t ) = i ∑ j ( ℏ ω j 2 ) 1 / 2 a ^ j ε j e i ( k j ⋅ r − ω j t ) {\displaystyle E^{(+)}(\mathbf {r} ,t)=i\sum _{j}\left({\frac {\hbar \omega _{j}}{2}}\right)^{1/2}{\hat {a}}_{j}\mathbf {\varepsilon } _{j}e^{i(\mathbf {k} _{j}\cdot \mathbf {r} -\omega _{j}t)}} where ε j {\displaystyle \mathbf {\varepsilon } _{j}} are the unit vectors of polarization; this expansion has the same form as the classical expansion except that now the field amplitudes a ^ j {\displaystyle {\hat {a}}_{j}} are operators.Glauber showed that, for an ideal photodetector situated at a point r {\displaystyle \mathbf {r} } in a radiation field, the probability of observing a photoionization event in this detector between time t {\displaystyle {t}} and t + d t {\displaystyle {\it {t}}+d{\it {t}}} is proportional to W I ( r , t ) d t {\displaystyle W_{I}(\mathbf {r} ,t)d{\it {t}}} , where W I ( r , t ) = ⟨ ψ ∣ E ( − ) ( r , t ) ⋅ E ( + ) ( r , t ) ∣ ψ ⟩ {\displaystyle {W_{I}(\mathbf {r} ,t)}=\langle \psi \mid {E^{(-)}(\mathbf {r} ,t)}\cdot {E^{(+)}(\mathbf {r} ,t)}\mid \psi \rangle } and | ψ ⟩ {\displaystyle |\psi \rangle } specifies the state of the field. Since the radiation field is a quantum-mechanical one, we do not know the exact properties of the incident light, and the probability should be averaged, as in the classical theory, to be proportional to ⟨ a ^ j † a ^ j ⟩ {\displaystyle \langle {\hat {a}}_{j}^{\dagger }{\hat {a}}_{j}\rangle } where the angular brackets mean an average over the light field. The significance of the quantum theory of coherence is in the ordering of the creation and destruction operators a ^ j † {\displaystyle {\hat {a}}_{j}^{\dagger }} and a ^ j {\displaystyle {\hat {a}}_{j}} : [ a ^ j , a ^ j † ] = 1 {\displaystyle [{\hat {a}}_{j},{\hat {a}}_{j}^{\dagger }]=1} Since a ^ j † a ^ j {\displaystyle {\hat {a}}_{j}^{\dagger }{\hat {a}}_{j}} is not equal to a ^ j a ^ j † {\displaystyle {\hat {a}}_{j}{\hat {a}}_{j}^{\dagger }} for a light field, the order makes the quantum statistical measurements (such as photon counting) quite different from the classical ones, i.e., the nonclassical properties of light, such as photon antibunching.Moreover, Glauber's theory of photodetection is of far-reaching fundamental significance to interpretation of quantum mechanics. The Glauber detection theory differs from the Born probabilistic interpretation, in that it expresses the meaning of physical law in terms of measured facts (relationships), counting events in the detection processes, without assuming the particle model of matter. These concepts quite naturally lead to a relational approach to quantum physics.

Photoemulsion

Photographic emulsion is a light-sensitive colloid used in film-based photography. Most commonly, in silver-gelatin photography, it consists of silver halide crystals dispersed in gelatin. The emulsion is usually coated onto a substrate of glass, films (of cellulose nitrate, cellulose acetate or polyester), paper, or fabric.Photographic emulsion is not a true emulsion, but a suspension of solid particles (silver halide) in a fluid (gelatin in solution).

Photogenic sneezing

Photographers of the African-American civil rights movement

Photograph: The Very Best of Ringo Starr

Photoglob

Photoetching

Photographic archive Gerola

Photoeye

A photoflash capacitor is an electrolytic capacitor used in flash cameras, professional flashes, and also in solid-state laser power supplies. Their usual purpose is to briefly power a high-voltage flash tube, used to illuminate a photographic subject or optically pump a laser rod. As flash tubes require very high current for a very short time to operate, photoflash capacitors are designed to supply high discharge current pulses without excessive internal heating.The principal properties of a capacitor are capacitance, working voltage, equivalent series resistance (ESR), equivalent series inductance (ESL), and working temperatureCompared with electrolytic capacitors usually used for power supply filtering at power frequency, a photoflash capacitor is designed to have lower ESR, ESL, and capacitance manufacturing tolerance, but does not need as high a working temperature.The light energy emitted by a flash is supplied by the capacitor, and is proportional to the product of the capacitance and the voltage squared; photoflash capacitors have capacitance in the range 80-160 microfarads (µF) and voltages from 180–330 volts for flash units built into small disposable and compact cameras, increasing for units delivering higher light energy. A typical manufacturer's range includes capacitors operating at 330–380V, with capacitance from 80 to 1,500 µF While normal electrolytic capacitors are often operated at not more than half their nominal voltage due to their high derating, photoflash capacitors are typically operated at their nominal working voltage (labelled as "WV" or "W.V." rather than just "V"). Photoflash capacitors are not subject to the high temperatures of cased electronic equipment in continuous operation, with nearby components and sometimes the capacitors themselves dissipating heat; they are often rated at a maximum operating temperature rate of typically 55 °C, compared to 85 °C–105 °C or more for capacitors for continuous use in electronic equipment. In most electronic applications an electrolytic capacitor can have a capacitance much larger than its nominal value without detracting from circuit performance; general-purpose electrolytics are often specified to have capacitance between 20% below and 80% above rated value, although tighter tolerances are available. The light energy of a flash is proportional to the capacitance and large variations are not acceptable, typical tolerance is -10+20%.Photoflash capacitors are designed to deliver a brief pulse of very high current, and are consequently sometimes used in railgun and coilgun designs.

Photograph is a photography book by Ringo Starr. The book is a collection of 240 photographs of Starr's that also serves as his autobiography through the photo captions. The title of the book is the also the title of his 1973 single "Photograph". The book was first published in 2013 in a deluxe 2,500-copy limited edition by Genesis Publications, and later in a mass edition in 2015.

Photographic Display Unit

Photograph 51 (disambiguation)

Photographic Society of America

A photocatalyst activity indicator ink (Paii) is a substance used to identify the presence of an underlying heterogeneous photocatalyst and to measure its activity. Such inks render visible the activity of photocatalytic coatings applied to various "self-cleaning" products. The inks contain a dyestuff that reacts to ultraviolet radiation in the presence of the photocatalytic agent in the coating.

Photoelasticity describes changes in the optical properties of a material under mechanical deformation. It is a property of all dielectric media and is often used to experimentally determine the stress distribution in a material, where it gives a picture of stress distributions around discontinuities in materials.

Photochemistry and Photobiology is a peer-reviewed scientific journal that publishes original research papers, rapid communications, research notes, technical notes, invited articles, and reviews covering photochemistry and photobiology. These topics relate to the interaction of light with living systems, the resulting biological reactions, related chemical and physical processes, and the relation of these to medicine and other disciplines.The editor in chief of Photochemistry and Photobiology is Jean Cadet.

Photocollage

Photodisintegration hypernova

Photograph (disambiguation)

Photographic art

Photochrom

Photochemical machining

Photodotis photinopa is a moth of the Gelechiidae family. It was described by Meyrick in 1920. It is found in South Africa.The wingspan is about 13 mm. The forewings are white and with a rather broad whitish-ochreous streak sprinkled with grey and dark fuscous running from the base beneath the costa to one-third, then obliquely deflected to a small round yellow-whitish spot edged with a few dark scales representing the second discal stigma, and a similar streak from the middle of the base to a more obscure similar spot representing the plical stigma. There is some grey irroration towards the costa at two-thirds, and two or three scales on the tornus. There is an apical spot of grey suffusion. The hindwings are light grey.

Photoelectron

The Photographic Display Unit, or PDU, was a large-format display system used by the Royal Air Force to present radar images for interpretation by a number of operators and commanders. Made by Kelvin Hughes, it projected a 6 feet (1.8 m) diameter image that could optionally be overlaid with a map and range rings. The PDU was originally designed for the ROTOR system and subsequent AMES Type 80-based Master Radar Stations. A smaller version with a 24 inches (610 mm) display was used onboard Royal Navy ships, and a larger version projected onto movie screens was used in the SAGE system in the US.

Photocatalysts

Photochemical solar

Photochemistry is the branch of chemistry concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet (wavelength from 100 to 400 nm), visible light (400 – 750 nm) or infrared radiation (750 – 2500 nm).In nature, photochemistry is of immense importance as it is the basis of photosynthesis, vision, and the formation of vitamin D with sunlight. Photochemical reactions proceed differently than temperature-driven reactions. Photochemical paths access high energy intermediates that cannot be generated thermally, thereby overcoming large activation barriers in a short period of time, and allowing reactions otherwise inaccessible by thermal processes. Photochemistry is also destructive, as illustrated by the photodegradation of plastics.

Photoglyphic

Photoelectric Flame Photometer

Photochemical Logic Gates

In chemistry, photocatalysis is the acceleration of a photoreaction in the presence of a catalyst. In catalysed photolysis, light is absorbed by an adsorbed substrate. In photogenerated catalysis, the photocatalytic activity (PCA) depends on the ability of the catalyst to create electron–hole pairs, which generate free radicals (e.g. hydroxyl radicals: •OH) able to undergo secondary reactions. Its practical application was made possible by the discovery of water electrolysis by means of titanium dioxide.

A photocarcinogen is a substance which causes cancer following illumination. This destructive effect often results from free radicals generated by the photocarcinogen. Many chemicals that are not carcinogenic can be photocarcinogenic. This can easily be understood from a photochemical perspective: The reactivity of a chemical substance itself might be low, but after illumination it transfers to the excited state. This excited state is chemically much more reactive and therefore potentially harmful to biological tissue.Melanin is not a photocarcinogen, because it dissipates the excitation energy into small amounts of heat (see photoprotection). Oxybenzone (a component of some sunscreens) is suspected owing to its skin penetrating qualities and its production of free radicals.

Photoelectric Work Function

Photochemical carbon dioxide reduction harnesses solar energy to convert CO2 into higher-energy products. The chemical conversion of CO2 already occurs on an industrial scale in the manufacture of solvents such as formic acid, but photochemical reduction differs in that it relies on a renewable energy source, the sun. Because CO2 is a greenhouse gas, there is environmental interest in producing artificial systems that are efficient photocatalysts, but the low turn-over rates of current methods have prohibited wide-scale industrial application.

Photochemical Equivalence Law

Photographic Memory

A photogram is a photographic image made without a camera by placing objects directly onto the surface of a light-sensitive material such as photographic paper and then exposing it to light. The usual result is a negative shadow image that shows variations in tone that depends upon the transparency of the objects used. Areas of the paper that have received no light appear white; those exposed through transparent or semi-transparent objects appear grey.The technique is sometimes called cameraless photography. It was used by Man Ray in his exploration of rayographs. Other artists who have experimented with the technique include László Moholy-Nagy, Christian Schad (who called them "Schadographs"), Imogen Cunningham and Pablo Picasso. Variations of the technique have also been used for scientific purposes.

Photoelectrochemical reduction of CO2 is a chemical process whereby carbon dioxide is reduced to carbon monoxide or hydrocarbons by the energy of incident light. This process needs to be catalyzed either homogeneously or heterogeneously in order to proceed, and current research is aimed at developing these catalysts, most of which are semiconducting materials. Semiconducting catalysts provide favourable electron transfer kinetics.Motivation for research in this area is strong due to the current attention to atmospheric carbon dioxide as the reduction of carbon dioxide would be one route for removal and sequestration. Furthermore, the reduced species may prove to be a valuable feedstock for other processes. If the incident light utilized is solar in nature then this process also potentially represents energy routes which combine renewable energy with CO2 reduction.

Photographic filters

Photocrom

In Germany, photo rights or "Bildrechte" are the copyrights that are attached to the "author" of the photograph and are specified in the "Law for Copyright and similar Protection" ("Gesetz über Urheberrecht und verwandte Schutzrechte"). These rights deal with rights of reproduction, distribution, modification, attribution, and prohibitions against illegal modification or reproduction. The ownership rights of a picture are treated under the broader "art copyright laws".

Photographic guidance

Photochromatic

Photogenis grandipinnis

Photograph: The Very Best of Ringo Starr (the last word visually rendered as ) is a career-spanning best-of compilation album by Ringo Starr and is the first such album since the releases of 1975's Blast from Your Past and 1989's Starr Struck: Best of Ringo Starr, Vol. 2. The release of the new collection coincided with the reissue of Starr's first four solo albums for EMI, in digital format, on 28 August 2007.The compilation debuted at number 26 on the UK Albums Chart on 2 September 2007.

Photoflash capacitor

"Photograph" was the very first single released by The Verve Pipe. Although not a mainstream success like their well-known hit "The Freshmen", it reached number 6 on the Alternative Songs chart, and number 17 on the Mainstream Rock Songs chart in 1996.

Photodotis spilodoma is a moth of the Gelechiidae family. It was described by Meyrick in 1918. It is found in South Africa.The wingspan is about 13 mm. The forewings are dark fuscous irrorated with whitish, the dorsal area on the anterior half of the wing is suffused with whitish-ochreous, anteriorly extending two-thirds across the wing. There is a blotch of blackish irroration representing the plical and first discal stigmata, and a small spot on the costa above it. A small brownish spot is found on the tornus, connected by a cloudy blackish dot surmounted by a similar ochreous dot with an indistinct dark second discal stigma. A small cloudy whitish spot is found on the costa at three-fourths and there are two short ochreous streaks above and two below apex, separated by blackish irroration. The hindwings are grey.

Photocathode

Photographic Horizons was a United States television series where panelists discussed the art and science of photography. The show aired on Wednesdays at 8:30pm on the now-defunct DuMont Television Network.

Photographic grey, also known as works grey, was a paint scheme commonly applied to steam locomotives during the period before colour photography became commonplace. It was applied to allow sharper, more detailed images of the locomotive to be recorded.

Photographic Society of America (PSA) is one of the largest, worldwide, non-profit organizations of its kind. Established in 1934, it is for casual shutterbugs, serious amateurs, and professional photographers. PSA has members in over 75 countries. Membership is currently about 5,500, with 35% outside the USA. The current president of the PSA is Elena McTighe, who took the role in October 2017.The mission of the society is to: promote the art and science of photography as a means of communication, image appreciation, and cultural exchange; provide education, information, inspiration, and opportunity for all persons interested in photography; and foster personal growth and expression, creativity, excellence, and ethical conduct in all aspects of photographic endeavor.Individual and photo organization memberships offer a wide variety of services and activities: a monthly journal; online photo galleries; image evaluation; study groups; courses; competitions; an annual conference; opportunities for recognition of photographic achievement and service; and discounts on photography-related products and services. Six divisions including: Pictorial (digital and prints), Nature, Travel, Photojournalism. and 3D; provide numerous services.The PSA holds several notable competitions throughout the year, including a Youth Showcase. Additionally PSA approves and oversees about 600 international photographic exhibitions in nearly 50 countries. These exhibitions are open to everyone to enter.

Photoconductive

Photoglycine

The Photographic Society of Madras, also known as PSM, is a photographic society based in Chennai city of India. Founded in 1857, it is the oldest photographic society in India and one of the oldest in the world. PSM was founded in 1857, with the objective of promoting the Art and Science of Photography. The Society was renamed as Madras Amateur Photographic Society in the mid-1880s and later it reverted to its original name and continues to be known as Photographic Society of Madras.

Photocoagulation

A photocyte is a cell that specializes in catalyzing enzymes to produce light (bioluminescence). Photocytes typically occur in select layers of epithelial tissue, functioning singly or in a group, or as part of a larger apparatus (a photophore). They contain special structures termed as photocyte granules. These specialized cells are found in a range of multicellular animals including ctenophora, coelenterates (cnidaria), annelids, arthropoda (including insects) and fishes. Although some fungi are bioluminescent, they do not have such specialized cells.Light production may first be triggered by nerve impulses which stimulate the photocyte to release the enzyme luciferase into a "reaction chamber" of luciferin substrate. In some species the release occurs continually without the precursor impulse via osmotic diffusion. Molecular oxygen is then actively gated through surrounding tracheal cells which otherwise limit the natural diffusion of oxygen from blood vessels; the resulting reaction with the luciferase and luciferin produces light energy and a by-product (usually carbon dioxide).Researchers once postulated that ATP was the source of reaction energy for photocytes, but since ATP only produces a fraction the energy of the luciferase reaction, any resulting light wave-energy would be too small for detection by a human eye. The wavelengths produced by most photocytes fall close to 490 nm; although light as energetic as 250 nm is reportedly possible .The variations of color seen in different photocytes are usually the result of color filters that alter the wavelength of the light prior to exiting the endoderm, thanks to the other parts of the photophore. The range of colors vary between bioluminescent species.The exact combinations of luciferase and luciferin types found among photocytes are specific to the species to which they belong. This would seem to be the result of consistent evolutionary divergence.

Photochopping

Photographic Lines

Photoentrainment

Photograph Smile (song)

Photochlorination is a chemical reaction which is initiated by light, in which either hydrogen is replaced by chlorine in a hydrocarbon compound or chlorine is reacted via an addition reaction to an aromatic or olefinic hydrocarbon. Photochlorination is carried out in addition to thermal and catalytic chlorination on an industrial scale, usually in the liquid phase, sometimes in the presence of inert solvents. The process is exothermic and proceeds as a chain reaction initiated by the homolytic cleavage of molecular chlorine into chlorine radicals by ultraviolet radiation.The chlorinated hydrocarbons produced via photochlorination are often only industrial intermediates and react with a large number of basic chemicals to secondary products such as alcohols, mercaptans, amines and carboxylic acids. The chemical industry uses low molecular weight chlorinated compounds, such as tetrachloromethane, as solvents. Higher molecular-weight chloroalkanes serve as insecticides, as flame retardants or as plasticizers in plastics and coatings. Chlorinated hydrocarbons are also used as intermediates in the chemical industry for the production of silicones or detergents.

Photochemical and Photobiological Sciences

Photographers' Mate

Photochemical carbon dioxide reduction harnesses solar energy to convert CO2 into higher-energy products. The chemical conversion of CO2 already occurs on an industrial scale in the manufacture of solvents such as formic acid, but photochemical reduction differs in that it relies on a renewable energy source, the sun.

Photochemical milling (disambiguation)

Photoglob Zürich

Photocopy machine

Photocorynus spiniceps

Photocopylore

Photoelectron effect

Photodermatol. Photoimmunol. Photomed.

Photobucket.com

Photogrammetric

Photodotis photinopa

Photograph retouching

Photofluorography (sometimes called just fluorography) is photography of X-ray images from a fluorescent screen. It is commonly used in some countries for chest X-ray screening, e.g. to diagnose tuberculosis or lung cancer (see Abreugraphy for more information on such usage of this technique).

Photographer's assistant

Photodissociation regions (or photon-dominated regions, or PDRs) are predominantly neutral regions of the interstellar medium in which far ultraviolet photons strongly influence the gas chemistry and act as the most important source of heat. They occur in any region of interstellar gas that is dense and cold enough to remain neutral, but that has too low a column density to prevent the penetration of far-UV photons from distant, massive stars. A typical and well-studied example is the gas at the boundary of a giant molecular cloud. PDRs are also associated with HII regions, reflection nebulae, active galactic nuclei, and Planetary nebulae. All the atomic gas and most of the molecular gas in the galaxy is found in PDRs.

Photoceptor

Photodegrade

The Photochemical Reflectance Index (PRI) is a reflectance measurement developed by John Gamon during his tenure as a postdoctorate fellow supervised by Christopher Field at the Carnegie Institution for Science at Stanford University. The PRI is sensitive to changes in carotenoid pigments (e.g. xanthophyll pigments) in live foliage. Carotenoid pigments are indicative of photosynthetic light use efficiency, or the rate of carbon dioxide uptake by foliage per unit energy absorbed.

Photogrammetrical

Photodotis spilodoma is a moth of the Gelechiidae family. It was described by Meyrick in 1918. It is found in South Africa.The wingspan is about 13 mm. The forewings are dark fuscous irrorated with whitish, the dorsal area on the anterior half of the wing is suffused with whitish-ochreous, anteriorly extending two-thirds across the wing. There is a blotch of blackish irroration representing the plical and first discal stigmata, and a small spot on the costa above it.

Photochromic sunglasses

Photographic Reconnaissance Unit

Photocopiers

In chemistry, photocatalysis is the acceleration of a photoreaction in the presence of a catalyst. In catalysed photolysis, light is absorbed by an adsorbed substrate. In photogenerated catalysis, the photocatalytic activity (PCA) depends on the ability of the catalyst to create electron–hole pairs, which generate free radicals (e.g. hydroxyl radicals: •OH) able to undergo secondary reactions.

Photochemical machining (PCM), also known as photochemical milling or photo etching, is a chemical milling process used to fabricate sheet metal components using a photoresist and etchants to corrosively machine away selected areas. This process emerged in the 1960s as an offshoot of the printed circuit board industry.

Photographic developing

Photocatalyst

Photographic Center of Skopelos

Photograph conservation

Photocorynus spiniceps is a species of anglerfish in the family Linophrynidae. It is in the monotypic genus Photocorynus.The known mature male individuals are 6.2–7.3 millimeters (0.25-0.3 inches), smaller than any other mature fish and vertebrate; the females, however, reach a significantly larger size of up to 50.5 millimeters (2 inches). (However, numerous fish species have both sexes reaching maturity below 20 millimeters (0.8 inches).)Like most other deepsea anglerfishes, Photocorynus spiniceps lures its prey into striking range using a bioluminescent sac at the end of an illicium, the highly modified first ray of the dorsal fin, and swallows the prey whole with the help of a distending jaw and a similarly distending stomach. Its prey can sometimes be as big as their own bodies. The male spends its life fused to its much larger female counterpart, therefore effectively turning her into a hermaphrodite. While the female takes care of swimming and eating, the male, with a large proportion of its body consisting of testes, is charged with the task of aiding reproduction.

Photoelectric Cell

Photocontact dermatitis

A photochemical logic gate is based on the photochemical intersystem crossing and molecular electronic transition between photochemically active molecules, leading to logic gates that can be produced.

Photochemical

Photoelastic effect

Photochromic lenses

Photographic Society of America (PSA) is one of the largest, worldwide, non-profit organizations of its kind. Established in 1934, it is for casual shutterbugs, serious amateurs, and professional photographers. PSA has members in over 75 countries. Membership is currently about 5,500, with 35% outside the USA.

Photochemical etching

Photocytes

Photochemical smog

The Photographic Society of Madras, also known as PSM, is a photographic society based in Chennai city of India. Founded in 1857, it is the oldest photographic society in India and one of the oldest in the world. PSM was founded in 1857, with the objective of promoting the Art and Science of Photography. The Society was renamed as Madras Amateur Photographic Society in the mid-1880s and later it reverted to its original name and continues to be known as Photographic Society of Madras. The Photographic Society of Madras is registered under the Tamil Nadu Societies Registration Act 1975. PSM organizes programs including, photo-walks, photo-tours, classes, workshops, salons and exhibitions, on most weeks of the year. Membership is open to anyone with an interest in photography.

A photofeed is a web feed that features image enclosures. They provide an easy, standard way to reference a list of images with title, date and description.Photofeeds are RSS enclosures of image file formats, similar to podcasts (enclosures of audio file formats).

Photocatalyst activity indicator inks

Photocorynus spiniceps is a species of anglerfish in the family Linophrynidae. It is in the monotypic genus Photocorynus.The known mature male individuals are 6.2–7.3 millimeters (0.25-0.3 inches), smaller than any other mature fish and vertebrate; the females, however, reach a significantly larger size of up to 50.5 millimeters (2 inches).

Photoelectrons

Photoelectrochemical reduction of CO2 is a chemical process whereby carbon dioxide is reduced to carbon monoxide or hydrocarbons by the energy of incident light. This process needs to be catalyzed either homogeneously or heterogeneously in order to proceed, and current research is aimed at developing these catalysts, most of which are semiconducting materials.

Photochromic complex

Photodermatitis due to plant

Photofluorography

Photoelectrotype

A photocyte is a cell that specializes in catalyzing enzymes to produce light (bioluminescence). Photocytes typically occur in select layers of epithelial tissue, functioning singly or in a group, or as part of a larger apparatus (a photophore). They contain special structures termed as photocyte granules. These specialized cells are found in a range of multicellular animals including ctenophora, coelenterates (cnidaria), annelids, arthropoda (including insects) and fishes.

In Germany, photo rights or "Bildrechte" are the copyrights that are attached to the "author" of the photograph and are specified in the "Law for Copyright and similar Protection" ("Gesetz über Urheberrecht und verwandte Schutzrechte"). These rights deal with rights of reproduction, distribution, modification, attribution, and prohibitions against illegal modification or reproduction. The ownership rights of a picture are treated under the broader "art copyright laws". Furthermore, if a museum or gallery owns a work of art or a photograph, they are permitted to make their own stipulations as to the selling of illustrations and reproductions of their property. This relates to the German legal concept of the right of owner to undisturbed possession. Wolf Vostell said: "Copyrights are like human rights".

Photocyte

Photocon

*Megacraspedus photinopa (Meyrick, 1920)

Photocell

Photobomb

Photochlorination is a chemical reaction which is initiated by light, in which either hydrogen is replaced by chlorine in a hydrocarbon compound or chlorine is reacted via an addition reaction to an aromatic or olefinic hydrocarbon. Photochlorination is carried out in addition to thermal and catalytic chlorination on an industrial scale, usually in the liquid phase, sometimes in the presence of inert solvents.

Photochromy

Photogenic Memory

Photograph (Air song)

Photografting

Photographic Society of Madras

Photoelectric magnitude

Photographic Society

Photographers of the American civil rights movement

Photocard Driving Licence

Photogenis pyrrhomelas

Photochem. Photobiol. Sci.

Photoelectric cell

Photochemical CO2 Reduction

Photochemical machining (PCM), also known as photochemical milling or photo etching, is a chemical milling process used to fabricate sheet metal components using a photoresist and etchants to corrosively machine away selected areas. This process emerged in the 1960s as an offshoot of the printed circuit board industry. Photo etching can produce highly complex parts with very fine detail accurately and economically.This process can offer economical alternatives to stamping, punching, laser or water jet cutting, or wire electrical discharge machining (EDM) for thin gauge precision parts. The tooling is inexpensive and quickly produced. This makes the process useful for prototyping and allows for easy changes in mass production. It maintains dimensional tolerances and does not create burrs or sharp edges. It can make a part in hours after receiving the drawing.PCM can be used on virtually any commercially available metal or alloy, of any hardness. It is limited to materials with a thickness of 0.0005 to 0.080 in (0.013 to 2.032 mm). Metals include aluminium, brass, copper, inconel, manganese, nickel, silver, steel, stainless steel, zinc and titanium.

Photochromic memory

Photodissociation region

Photographed

Photocomics

Photographer as Witness: A Portrait of Domestic Violence

Photograph (book)

Photofragment-ion imaging

Photodiodes

Photograph (Ed Sheeran song)

Photochromic lens

Photochemical milling

Photograbber

Photocentrism

Photocure ASA

Photocrime

Photoelectric efficiency

Photocarcinogen

Photochlorination

Photoconductive atomic force microscopy

Photographic emulsion

Photofrin

Photoelectric Effect

The Photographic Display Unit, or PDU, was a large-format display system used by the Royal Air Force to present radar images for interpretation by a number of operators and commanders. Made by Kelvin Hughes, it projected a 6 feet (1.8 m) diameter image that could optionally be overlaid with a map and range rings. The PDU was originally designed for the ROTOR system and subsequent AMES Type 80-based Master Radar Stations.

Photocatalysis

Photoconduction

Photographer's Gallery

Photoconductive effect

Photodember

A photoflash battery is a specialized zinc-carbon battery optimized to provide a high electric current output for a short duration of time, such as required to fire a flashbulb. Service life for this battery in flashlight service was short, since flashlights required a lower but continuous long duration current.Photoflash cells were in production during the flashbulb era, and were slowly phased out as alkaline cells came into general usage.

Photocatalytic water splitting is an artificial photosynthesis process with photocatalysis in a photoelectrochemical cell used for the dissociation of water into its constituent parts, hydrogen (H2) and oxygen (O2), using either artificial or natural light. Theoretically, only solar energy (photons), water, and a catalyst are needed. This topic is the focus of much research, but thus far no technology has been commercialized.Hydrogen fuel production has gained increased attention as oil and other nonrenewable fuels become increasingly depleted and expensive. Methods such as photocatalytic water splitting are being investigated to produce hydrogen, a clean-burning fuel. Water splitting holds particular promise since it utilizes water, an inexpensive renewable resource. Photocatalytic water splitting has the simplicity of using a powder in solution and sunlight to produce H2 and O2 from water and can provide a clean, renewable energy, without producing greenhouse gases or having many adverse effects on the atmosphere.

Photodotis pellochroa

Photoelectrochemical reduction of CO2

Photodermatol Photoimmunol Photomed

Photocorynus

Photographic catadioptric lens

Photograph printer

Photographic emulsion is a light-sensitive colloid used in film-based photography. Most commonly, in silver-gelatin photography, it consists of silver halide crystals dispersed in gelatin. The emulsion is usually coated onto a substrate of glass, films (of cellulose nitrate, cellulose acetate or polyester), paper, or fabric.Photographic emulsion is not a true emulsion, but a suspension of solid particles (silver halide) in a fluid (gelatin in solution). However, the word emulsion is customarily used in a photographic context. Gelatin or gum arabic layers sensitized with dichromate used in the dichromated colloid processes carbon and gum bichromate are sometimes called emulsions. Some processes do not have emulsions, such as platinum, cyanotype, salted paper, or kallitype.

Photographer (DJs)

Photograph (The Verve Pipe song)

Photograph Smile is the fifth studio album by English singer-songwriter Julian Lennon.

Photograph - Melanie album

Photoflash bomb

Photoelectrotyping

Photographic Alliance of Great Britain

Photoelectron spectrum

Photograph (Ariel Rivera album)

Photochromic dyes

Photochromic

Photoboy

Photoelectrochemical cells

Photographic album

Photodisruption is a form of minimally invasive surgery used in ophthalmology, utilizing infrared Nd:YAG lasers to form plasma ("lightning bolt"), which then causes acoustic shock waves ("thunderclap") which then in turn affects tissue. The tissue ruptures as a result of the vapor bubble produced by the laser; the temperature required to produce this effect is between 100 and 305 °C.Because the infrared laser is invisible to the surgeon's eye, typically a companion HeNe laser is used in conjunction. However, the eye lens acts as a prism, so the infrared light bends at a shallower angle than the red light, causing chromatic aberration. This means the area highlighted by the HeNe laser is not precisely the area being affected Nd:YAG laser, and therefore some surgical lasers have an added adjustment to compensate.The first successful use of photodisruption was in 1972, on a case of trabecular meshwork. Photodisruption came to wide use in the early 1980s for the treatment of extracapsular cataract extraction. The technique is most commonly used for lithotripsy of unrinary calculi and the treatment of posterior capsulotomy of the lens. When used in corneal surgery, picosecond and nanosecond disruptors are used on the lamellae of the corneal stroma, and the method may be preferable as it leaves the epithelium and Bowman's membrane unharmed. This modifies the outer corneal curvature, which affects the refractive property of the eye.

Photofinish

In his historic paper entitled "The Quantum Theory of Optical Coherence," Roy J. Glauber set a solid foundation for the quantum electronics/quantum optics enterprise. The experimental development of the optical maser and later laser at that time had made the classical concept of optical coherence inadequate. Glauber started from the quantum theory of light detection by considering the process of photoionization in which a photodetector is triggered by an ionizing absorption of a photon.

Photoepilation

Photocatalyst activity indicator ink

Photocromatic

Photoelasticity describes changes in the optical properties of a material under mechanical deformation. It is a property of all dielectric media and is often used to experimentally determine the stress distribution in a material, where it gives a picture of stress distributions around discontinuities in materials. Photoelastic experiments (also informally referred to as photoelasticity) are an important tool for determining critical stress points in a material, and are used for determining stress concentration in irregular geometries.

The Photographic Convention of United Kingdom (PCUK) was founded in 1886 and held its first convention in the city of Derby, England, in August of that year.The founding members were a mixture of professional photographers and wealthy amateurs.

Photodiode array

Photoelectric cells

Photogenic sneeze

Photochemistry & Photobiology

Photodegradable

Photochop

Photochemical cycle

Photodehydrogenation

Photocoagulator

Photographers Association of America

Photoelectricity

Photographic artifact

Photochemical internalization

Photochart

Photochemical reaction center

Photochemical fog

Photochemical Reflectance Index

Photoelectrolysis, also known as water splitting, occurs in a photoelectrochemical cell when light is used as the energy source for the electrolysis of water, producing dihydrogen which can be used as a fuel. This process is one route to a "hydrogen economy", in which hydrogen fuel is produced efficiently and inexpensively from natural sources without using fossil fuels. In contrast, steam reforming usually or always uses a fossil fuel to obtain hydrogen.

Photodisc

"Photograph" is a song recorded by the English singer-songwriter, Ed Sheeran, for his second studio album, × (2014). Sheeran wrote the song with Snow Patrol member, Johnny McDaid, who had a piano loop from which the composition developed. After recording several versions with other producers, Sheeran eventually solicited help from Jeff Bhasker; the collaboration generated a version that Bhasker further enhanced for months.

Photofit

Photographic assistant

Photodotis is a genus of moth in the family Gelechiidae.

A photoflash bomb, or flash bomb, is explosive ordnance dropped by aircraft, usually military surveillance aircraft, designed to detonate above ground to create an extremely bright flash of light. These bombs, which are capable of producing light at an intensity of up to hundreds of millions of candlepower, assist surveillance aircraft in taking nighttime aerial photos without the need to fly low to the ground which would make it vulnerable to possible enemy detection.

Photofinishing

Photochromic lenses are optical lenses that darken on exposure to specific types of light of sufficient intensity, most commonly ultraviolet (UV) radiation. In the absence of activating light the lenses return to their clear state. Photochromic lenses may be made of glass, polycarbonate, or another plastic. They are principally used in eyeglasses that are dark in bright sunlight, but clear in low ambient light conditions.

Photodetectors

Photoestrogen

Photochemistry is the branch of chemistry concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet (wavelength from 100 to 400 nm), visible light (400 – 750 nm) or infrared radiation (750 – 2500 nm).In nature, photochemistry is of immense importance as it is the basis of photosynthesis, vision, and the formation of vitamin D with sunlight.

Photochromogen

Photocrime is an American television crime drama that was broadcast on ABC from September 28, 1949, until December 14, 1949. The program was also known as Look Photocrime.The program's title and premise -- "that photographs often possess clues that are often overlooked" initially -- came from an illustrated fictional crime series that ran in Look magazine, and the program was produced in association with Look. However, the concept of an illustrated mystery began with Denis Horton, an insurance clerk in England. The Weekly Illustrated published the first Photocrime in 1935. By 1937, Photocrime was also printed in a number of American newspapers.Chuck Webster portrayed police inspector Hannibal Cobb. Murray Burnett was the producer and writer. Babette Henry was the director.Lack of a sponsor brought the program to an end after 13 weeks.

Photocopied

Photoconductive cell

Photocopier

Photogr. Cult.

Photocure ASA is a Norwegian specialty pharma company that develops and sells pharmaceuticals and medical devices based on proprietary photodynamic technology. Photocure's strategy in cancer is to continue the commercialization of Hexvix for bladder cancer diagnostics, and continue the development of the cancer portfolio and out-license prior to phase III studies. This strategy is based on a strong platform of intellectual property in photodynamic therapy.

In photography and videography, a filter is a camera accessory consisting of an optical filter that can be inserted into the optical path. The filter can be of a square or oblong shape and mounted in a holder accessory, or, more commonly, a glass or plastic disk in a metal or plastic ring frame, which can be screwed into the front of or clipped onto the camera lens.Filters modify the images recorded.

Photographers of Bangladesh

President

Photographic filter

Photoconductivity is an optical and electrical phenomenon in which a material becomes more electrically conductive due to the absorption of electromagnetic radiation such as visible light, ultraviolet light, infrared light, or gamma radiation.When light is absorbed by a material such as a semiconductor, the number of free electrons and electron holes increases and raises its electrical conductivity. To cause excitation, the light that strikes the semiconductor must have enough energy to raise electrons across the band gap, or to excite the impurities within the band gap. When a bias voltage and a load resistor are used in series with the semiconductor, a voltage drop across the load resistors can be measured when the change in electrical conductivity of the material varies the current through the circuit.Classic examples of photoconductive materials include :the conductive polymer polyvinylcarbazole, used extensively in photocopying (xerography);lead sulfide, used in infrared detection applications, such as the U.S. Sidewinder and Soviet (now Russian) Atoll heat-seeking missiles;selenium, employed in early television and xerography.

Photoconductive Atomic Force Microscopy

Photograph: The Very Best of Ringo Starr (the last word visually rendered as ) is a career-spanning best-of compilation album by Ringo Starr and is the first such album since the releases of 1975's Blast from Your Past and 1989's Starr Struck: Best of Ringo Starr, Vol. 2. The release of the new collection coincided with the reissue of Starr's first four solo albums for EMI, in digital format, on 28 August 2007.The compilation debuted at number 26 on the UK Albums Chart on 2 September 2007. This achievement represented Starr's highest peak on that chart since 1974, when Goodnight Vienna reached number 30. Photograph: The Very Best of Ringo Starr stayed in the UK top 100 for three weeks. The album also had a two-week chart run in the United States, where it debuted at number 130 with 5,426 copies sold during the first week of release.

Photograph manipulation

Photofragment ion imaging or, more generally, Product Imaging is an experimental technique for making measurements of the velocity of product molecules or particles following a chemical reaction or the photodissociation of a parent molecule. The method uses a two-dimensional detector, usually a microchannel plate, to record the arrival positions of state-selected ions created by resonantly enhanced multi-photon ionization (REMPI).

Photograph of Mary

Photoelectric spectrum

Photogenic

Photoelectrochemical cell

Photoelasticity tensor

Photochemical reflectance Index

Photog

Photochemistry and Photobiology

Photodisruption is a form of minimally invasive surgery used in ophthalmology, utilizing infrared Nd:YAG lasers to form plasma ("lightning bolt"), which then causes acoustic shock waves ("thunderclap") which then in turn affects tissue.

Photographic

Photodynamic Immunotherapy

Photographic artifacts

The Photographic Convention of United Kingdom (PCUK) was founded in 1886 and held its first convention in the city of Derby, England, in August of that year.The founding members were a mixture of professional photographers and wealthy amateurs. Prominent professional photographers present at the first meeting included William England, principal photographer with the London Stereoscopic Company; Richard Keene, who later became a member of The Brotherhood of the Linked Ring and Alfred Seaman who established a large number of studios across the Midlands and North of England.The leading pictorialist photographer Henry Peach Robinson was an early member and was elected President in 1896. William Crooke the prominent Scottish professional photographer was elected president in 1899. Many of the founding members were also members of the Royal Photographic Society but sought to establish an organisation with a more informal and sociable purpose- ‘combining the features of a pleasurable outing with photographic mental friction.’Attendance at the first meeting was 48 but grew rapidly over coming years to reach 328 by the 1898 event. The pattern of the convention was to choose a town where they would be 'hosted' by a local photographic society. A large hotel was chosen as the convention headquarters and three to four days were devoted to a programme of lectures, outings, exhibitions and dinners.Conventions of the Victorian era were held in:1886 Derby1887 Glasgow1888 Birmingham1889 London1890 Chester1892 Edinburgh1893 Plymouth1894 Dublin1895 Shrewsbury1896 Leeds1897 Great Yarmouth1898 Glasgow1899 Gloucester1900 Newcastle upon Tyne1901 OxfordDuring the nineteenth century the Convention was a lively focus for debate and experiment around photography. After the First World War interest waned and the PCUK was kept running by an increasingly ageing and declining membership. It finally ceased operating in 1935.

Photographers' abbreviations

Photographer Terry Morris

Photoengraving

Photograph processing

Photochemical Assessment Monitoring Station

Photochromic glass

Photodotis photinopa is a moth of the Gelechiidae family. It was described by Meyrick in 1920. It is found in South Africa.The wingspan is about 13 mm.

Photoengraving is a process that uses a light-sensitive photoresist applied to the surface to be engraved to create a mask that shields some areas during a subsequent operation which etches, dissolves, or otherwise removes some or all of the material from the unshielded areas. Normally applied to metal, it can also be used on glass, plastic and other materials.A photoresist is selected which is resistant to the particular acid or other etching compound to be used.

Photodermatitis

Photoconceptualism

Photographic Society of Japan awards

Photographic Art Society

Photographic grey

Museum of Photography of Skopelos, aka the Photographic Center of Skopelos, was a museum and seasonal exhibition venue in Skopelos, the Sporades, Greece. It hosted workshops and significant retrospectives of the work of photographers Robert Capa, Herbert List and Josef Koudelka, among others.

Photochemical Reaction

Photograph 51

Photoelectrochemical process

Photoelectrolysis

Photochemical Assessment Monitoring Stations are ambient air monitoring sites mandated by the 1990 Clean Air Act amendments. Placed in areas of high ozone, they monitor volatile organic compounds, nitrogen oxides, ozone and meteorological parameters. The data is used by the Environmental Protection Agency to understand the causes of ozone pollution and monitor improvement.

Photoemission Electron microscopy (PEEM, also called photoelectron microscopy, PEM) is a widely used type of emission microscopy. PEEM utilizes local variations in electron emission to generate image contrast. The excitation is usually produced by UV light, synchrotron radiation or X-ray sources. PEEM measures the coefficient indirectly by collecting the emitted secondary electrons generated in the electron cascade that follows the creation of the primary core hole in the absorption process. PEEM is a surface sensitive technique because the emitted electrons originate from a very shallow layer. In physics, this technique is referred to as PEEM, which goes together naturally with low-energy electron diffraction (LEED), and low-energy electron microscopy (LEEM). In biology, it is called photoelectron microscopy (PEM), which fits with photoelectron spectroscopy (PES), transmission electron microscopy (TEM), and scanning electron microscopy (SEM).

Photodraw

"Photograph" is a song recorded by the English singer-songwriter, Ed Sheeran, for his second studio album, × (2014). Sheeran wrote the song with Snow Patrol member, Johnny McDaid, who had a piano loop from which the composition developed. After recording several versions with other producers, Sheeran eventually solicited help from Jeff Bhasker; the collaboration generated a version that Bhasker further enhanced for months. The ballad derives its music primarily from an acoustic guitar, piano and programmed drums. With visually descriptive lyrics, it discusses a long-distance relationship inspired by Sheeran's own experience of being away from his then-girlfriend while he was on tour.The song received generally positive commentary from critics, who noted the lyrics and Sheeran's use of imagery. "Photograph" served as the fifth and final single from the album. It reached the top five on the main singles charts in more than five countries. In the US, where it peaked at No. 10, "Photograph" became the third single from the album to have reached within the top ten. In the UK, it reached No. 15 and has since been certified platinum for sales of 600,000 units. The single has also been certified double platinum in Australia and Canada, and platinum in New Zealand and Italy.The single's release on 11 May 2015 followed the premiere of the music video on 9 May 2015. The video is a montage of real home footage of Sheeran's infancy, childhood and adolescence, providing insight on his private early life such as his inclination to playing music instruments and fondness of Lego. The video was nominated for Best Video at the 2016 Brit Awards. Sheeran performed the song on television shows and on his x Tour, which ran from 2014 to 2015.On 9 June 2016, it was revealed that Sheeran was being sued by songwriters Martin Harrington and Thomas Leonard, writers of Matt Cardle's 2011 single "Amazing", for $20 million for copyright infringement for note-for-note plagiarism. The lawsuit was privately settled in April 2017, with no admission of guilt.

Photocopying Machine

Photoglo

Photodilus

Photoelasticity

Photoconductor

Photochromy is the art or process of reproducing colors by photography.[Note] Not to be confused with Photochromism (a reversible color change induced by light energy). See Photochromism. Furthermore, a Photochrom is not the result of the photochromy process.

Photographers/Aspen was a stock photo agency based in Aspen, Colorado started by National Geographic photographers Nicholas DeVore III, Jonathan Wright, David Hiser and Paul Chesley in 1984. In the 1990s the agency collaborated with Tony Stone Images and Getty Images before disbanding in 2000.

Photochem Photobiol Sci

Photograoh

A photoflash bomb, or flash bomb, is explosive ordnance dropped by aircraft, usually military surveillance aircraft, designed to detonate above ground to create an extremely bright flash of light. These bombs, which are capable of producing light at an intensity of up to hundreds of millions of candlepower, assist surveillance aircraft in taking nighttime aerial photos without the need to fly low to the ground which would make it vulnerable to possible enemy detection. Due to the advent of better nighttime optics, satellite imagery, and stealth aircraft, these bombs are no longer used by the military.

Photodotis palens

Photograph Boy

Photochemistry

Photoconductivity

Photochromatic lens

Photoelectrolysis, also known as water splitting, occurs in a photoelectrochemical cell when light is used as the energy source for the electrolysis of water, producing dihydrogen which can be used as a fuel. This process is one route to a "hydrogen economy", in which hydrogen fuel is produced efficiently and inexpensively from natural sources without using fossil fuels. In contrast, steam reforming usually or always uses a fossil fuel to obtain hydrogen. Photoelectrolysis is sometimes known colloquially as the hydrogen holy grail for its potential to yield a viable alternative to petroleum as a source of energy; such an energy source would supposedly come without the sociopolitically undesirable effects of extracting and using petroleum.Some researchers have practiced photoelectrolysis by means of a nanoscale process. Nanoscale photoelectrolysis of water could someday reach greater efficiency than that of "traditional" photoelectrolysis. Semiconductors with bandgaps smaller than 1.7 eV would ostensibly be required for efficient nanoscale photoelectrolysis using light from the Sun.Devices based on hydrogenase have also been investigated.

Photograph copyright (Germany)

Photocatalytic water splitting

Photographic grey, also known as works grey, was a paint scheme commonly applied to steam locomotives during the period before colour photography became commonplace. It was applied to allow sharper, more detailed images of the locomotive to be recorded. The first photographs of railways and their locomotives were made by private individuals, but by the 1860s the railway companies themselves were keen to create official photographs of the highest quality possible of their latest designs, which led to the adoption of photographic grey in railway photography.

Photoemission Electron microscopy (PEEM, also called photoelectron microscopy, PEM) is a widely used type of emission microscopy. PEEM utilizes local variations in electron emission to generate image contrast. The excitation is usually produced by UV light, synchrotron radiation or X-ray sources. PEEM measures the coefficient indirectly by collecting the emitted secondary electrons generated in the electron cascade that follows the creation of the primary core hole in the absorption process.

Photodotis spilodoma

Photograph conservator

Photoelectric smoke detector

Photocopying

Photodecomposition

Photochlor