Photo-electrograph Pho`to-e·lec"tro·graph noun [ See Photo- ; Electrograph .] (Meteor.) An electrometer registering by photography.

Photo-electrotype Pho`to-e·lec"tro·type noun (Print.) An electrotype plate formed in a mold made by photographing on prepared gelatine, etc.

Photo-engrave Pho`to-en·grave" transitive verb [ imperfect & past participle Photo-engraved ; present participle & verbal noun Photo-engraving .] [ Photo- + engrave .] To engrave by a photomechanical process; to make a photo-engraving of. -- Pho`to-en*grav"er noun

Photo-engraving Pho`to-en·grav"ing noun [ Photo- + engraving .] The process of obtaining an etched or engraved plate from the photographic image, to be used in printing; also, a picture produced by such a process.

Photo-epinasty Pho`to-ep"i·nas`ty noun [ See Photo- , and Epinastic .] (Botany) A disproportionately rapid growth of the upper surface of dorsiventral organs, such as leaves, through the stimulus of exposure to light. Encyc. Brit.

Photo-etch Pho`to-etch" transitive verb [ imperfect & past participle Photo-etched ; present participle & verbal noun Photo-etching .] [ Photo- + etch .] To engrave, or make an engraving of, by any photomechanical process involving etching of the plate.

Photo-etching Pho`to-etch"ing noun A photo- engraving produced by any process involving the etching of the plate.

Photobacterium Pho`to·bac·te"ri·um noun [ New Latin See Photo- , and Bacterium .] (Bacteriol.) A genus including certain comma-shaped marine bacteria which emit bluish or greenish phosphorescence. Also, any microörganism of this group.

Photobiotic Pho`to·bi·ot"ic adjective [ Photo- + biotic .] (Biol.) Requiring light to live; incapable of living without light; as, photobiotic plant cells.

Photoceramics Pho`to·ce·ram"ics noun Art or process of decorating pottery with photographically prepared designs. -- Pho`to*ce*ram"ic adjective

Photochemical Pho`to·chem"ic·al adjective [ Photo- + chemical .] (Chemistry) Of or pertaining to chemical action of light, or produced by it; as, the photochemical changes of the visual purple of the retina.

Photochemistry Pho`to·chem"is·try noun [ Photo- + chemistry .] (Chemistry) The branch of chemistry which relates to the effect of light in producing chemical changes, as in photography.

Photochromic, Photochromatic Pho`to·chro"mic, Pho`to·chro·mat"ic adjective Of or pertaining to photochromy; produced by photochromy.

Photochromography Pho`to·chro·mog"ra·phy noun [ Photo- + Greek ... color + -graphy .] Art or process of printing colored photographs.

Photochromoscope Pho`to·chro"mo·scope noun [ Photo- + Greek ... color + -scope .] 1. A device for giving shifting effects of color to a photograph. The unmounted print, made translucent, is illuminated from behind with colored light.

2. A combination of three optical lanterns for projecting objects on a screen in the colors of nature. The images of three partial photographs taken through color screens (red, green, and blue, respectively) are superimposed. Each image is given its own primary color, and these colors blend and reproduce the colors of the object.

Photochromotype Pho`to·chro"mo·type noun [ Photo- + Greek ... color + -type .] A colored print made photomechanically.

Photochromotype Pho`to·chro"mo·type transitive verb To represent by a colored print made by any photomechanical process.

Photochromotypy Pho`to·chro"mo·typ`y noun The art of making photochromotypes.

Photochromy Pho·toch"ro·my noun [ Photo- + Greek ... color.] The art or process of reproducing colors by photography.

Photochronograph Pho`to·chron"o·graph noun [ Photo- + chronograph .] 1. (Physics) An instrument for recording minute intervals of time. The record is made by the power of a magnetic field, due to an electric signaling current, to turn the plane of polarization of light. A flash, coinciding in time and duration with the signal, is thus produced and is photographed on a moving plate.

2. (Astron.) An instrument for the photographic recording of star transits.

Photochronography Pho`to·chro·nog"ra·phy noun Art of recording or measuring intervals of time by the photochronograph. -- Pho`to*chron`o*graph"ic , - graph"ic*al adjective -- - graph"ic*al*ly , adverb

Photodrome Pho"to·drome noun [ Photo- + Greek ... to run.] (Physics) An apparatus consisting of a large wheel with spokes, which when turning very rapidly is illuminated by momentary flashes of light passing through slits in a rotating disk. By properly timing the succession of flashes the wheel is made to appear to be motionless, or to rotate more or less slowly in either direction.

Photodynamics Pho`to·dy·nam"ics noun [ Photo- + dynamics .] (Plant Physiol.) The relation of light to the movements of plants and their organs; the study of the phenomena of curvatures induced by the stimulus of light. -- Pho`to*dy*nam"ic , Pho`to*dy*nam"ic*al adjective

Photogalvanography Pho`to·gal`va·nog"ra·phy noun [ Photo- + galvanography .] The art or process of making photo-electrotypes. Sir D. Brewster.

Photogen Pho"to·gen noun [ Photo- + - gen .] (Chemistry) A light hydrocarbon oil resembling kerosene. It is obtained by distilling coal, paraffin, etc., and is used as a lubricant, illuminant, etc. [ Written also photogene .]

Photogene Pho"to·gene noun [ See Photogen .] 1. A photograph. [ Obsoles.]

2. A more or less continued impression or image on the retina. H. Spencer.

Photogenic Pho`to·gen"ic adjective Of or pertaining to photogeny; producing or generating light.

Photogeny Pho·tog"e·ny noun [ See Photogen .] See Photography . [ Obsoles.]

Photoglyphic Pho`to·glyph"ic adjective [ Photo- + Greek ... to engrave.] Pertaining to the art of engraving by the action of light. [ Written also photoglyptic .]

Photoglyphic engraving , a process of etching on copper, steel, or zinc, by means of the action of light and certain chemicals, so that from the plate impressions may be taken. Sir D. Brewster.

Photoglyphy Pho·tog"ly·phy noun Photoglyphic engraving. See under Photoglyphic .

Photoglyptic Pho`to·glyp"tic adjective Same as Photoglyphic .

Photogram Pho"to·gram noun [ Photo- + -gram .] A photograph. [ R.]

Photogrammeter Pho`to·gram"me·ter noun [ See Photogram ; -meter .] A phototheodolite, or a camera designed for use in photogrammetry. -- Pho`to*gram*met"ric , Pho`to*gram*met"ric*al adjective

Photogrammetry Pho`to·gram"me·try noun [ Photogram + metry .] A method of surveying or map making by photography, used also in determining the height and motions of clouds, sea waves, and the like.

Photograph Pho"to·graph noun [ Photo- + -graph .] A picture or likeness obtained by photography.

Photograph Pho"to·graph transitive verb [ imperfect & past participle Photographed ; present participle & verbal noun Photographing .] To take a picture or likeness of by means of photography; as, to photograph a view; to photograph a group.

He makes his pen drawing on white paper, and they are afterwards photographed on wood.

Hamerton.

Also used figuratively.

He is photographed on my mind.

Lady D. Hardy.

Photograph Pho"to·graph intransitive verb To practice photography; to take photographs.

Photographer Pho·tog"ra·pher noun One who practices, or is skilled in, photography.

Photographic, Photographical Pho`to·graph"ic, Pho`to·graph"ic·al adjective [ Confer French photographique .] Of or pertaining to photography; obtained by photography; used ib photography; as a photographic picture; a photographic camera. -- Pho`to*graph"ic*al*ly , adverb

Photographic printing , the process of obtaining pictures, as on chemically prepared paper, from photographic negatives, by exposure to light.

Photographist Pho·tog"ra·phist noun A photographer.

Photographometer Pho·tog"ra·phom"e·ter noun [ Photograph + -meter .] (Photog.) An instrument for determining the sensibility of the plates employed in photographic processes to luminous rays.

Photographone Pho·tog"ra·phone noun [ See Photograph ; -phone .] A device, consisting essentially of an electric arc and a camera, by which a series of photographs of the variations of the arc due to sound waves are obtained for reproduction by means of a selenium cell and a telephone.

Photography Pho·tog"ra·phy noun [ Photo- + -graphy : confer French photographie .] 1. The science which relates to the action of light on sensitive bodies in the production of pictures, the fixation of images, and the like.

2. The art or process of producing pictures by this action of light.

» The well-focused optical image is thrown on a surface of metal, glass, paper, or other suitable substance, coated with collodion or gelatin, and sensitized with the chlorides, bromides, or iodides of silver, or other salts sensitive to light. The exposed plate is then treated with reducing agents, as pyrogallic acid, ferrous sulphate, etc., to develop the latent image. The image is then fixed by washing off the excess of unchanged sensitive salt with sodium hyposulphite ( thiosulphate ) or other suitable reagents.

Photogravure Pho`to·grav"ure noun [ French] A photoengraving; also, the process by which such a picture is produced.

Photoheliograph Pho`to·he"li·o·graph noun [ Photo- + heliograph .] (Physics) A modified kind of telescope adapted to taking photographs of the sun.

Photoheliometer Pho`to·he`li·om"e·ter noun [ Photo- + heliometer .] (Astron.) A double- lens instrument for measuring slight variations of the sun's diameter by photography, utilizing the common chord of two overlapping images.

Photolithograph Pho`to·lith"o·graph noun [ Photo- + lithograph .] A lithographic picture or copy from a stone prepared by the aid of photography.

Photolithograph Pho`to·lith"o·graph transitive verb To produce (a picture, a copy) by the process of photolithography.

Photolithographer Pho`to·li·thog"ra·pher noun One who practices, or one who employs, photolithography.

Photolithographic Pho`to·lith`o·graph"ic noun Of or pertaining to photolithography; produced by photolithography.

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