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.
Pho`to*grav"ure (?), n. [F.] A photoengraving; also, the process by
which such a picture is produced.
Pho`to*he"li*o*graph (?), n. [Photo- + heliograph.] (Physics) A
modified kind of telescope adapted to taking photographs of the sun.
Pho`to*lith"o*graph (?), n. [Photo- + lithograph.] A lithographic
picture or copy from a stone prepared by the aid of photography.
Pho`to*lith"o*graph, v. t. To produce (a picture, a copy) by the
process of photolithography.
Pho`to*li*thog"ra*pher (?), n. One who practices, or one who employs,
photolithography.
Pho`to*lith`o*graph"ic (?), n. Of or pertaining to photolithography;
produced by photolithography.
Pho`to*li*thog"ra*phy (?), n. The art or process of producing
photolithographs.
{ Pho`to*log"ic (?), Pho`to*log"ic*al (?), } a. Pertaining to
photology, or the doctrine of light.
Pho*tol"o*gist (?), n. One who studies or expounds the laws of light.
Pho*tol"o*gy (?), n. [Photo- + -logy: cf. F. photologie.] The doctrine
or science of light, explaining its nature and phenomena; optics.
Pho`to*mag*net"ic (?), a. Of or pertaining to photomagnetism.
Pho`to*mag"net*ism (?), n. The branch of science which treats of the
relation of magnetism to light.
Pho`to*me*chan"ic*al (?), a. Pertaining to, or designating, any
photographic process in which a printing surface is obtained without
the intervention of hand engraving.
Pho*tom"e*ter (?), n. [Photo- + -meter: cf. F. photomËtre.] (Physics)
An instrument for measuring the intensity of light, or, more
especially, for comparing the relative intensities of different lights,
or their relative illuminating power.
{ Pho`to*met"ric (?), Pho`to*met"ric*al (?), } a. [Cf. F.
photomÈtrique.] Of or pertaining to photometry, or to a photometer.
Pho*tom`e*tri"cian (?), n. One engaged in the scientific measurement of
light.
Pho*tom"e*try (?), n. [Cf. F. photomÈtrie.] That branch of science
which treats of the measurement of the intensity of light.
Pho`to*mi"cro*graph (f`t*m"kr*grf), n. [Photo- + micro + -graph.] 1. An
enlarged or macroscopic photograph of a microscopic object. See
Microphotograph.