Lamp for Dark Room Lead, Acetate of
Lamp for Dark Room. All lamps should be fitted with one or more screens of ruby or orange glass, so as to decrease or increase the light as desired. Every amateur should comprise amongst his travelling paraphernalia one or two square feet of ruby or golden fabric; by means of this a lamp may be im-provised from an ordinary candle, or night-light, or a Chinese lantern, or the side may be knocked out of a card-board hat-box. The author has before now changed plates when away from home by the aid of this little piece of ruby cloth by placing a candle in the empty fire-grate, and the ruby cloth over the bars. (See Dark Room.)
Lampblack. The very light form of carbon produced by burning pitch, resin, or any other smoky substance with limited access of air, and collecting the soot formed.
Landscape Lens. See Lens.
Lantern, Magic, Megalographic, or Optical. See Magic-Lantern.
Lantern Slides. See Line-drawings, to Copy; Hydro-quinone; Emulsion; and Albumen Process; also see De-velopment and Developers for general instructions as to the development of lantern slide transparencies made on commercial plates.
Lantemoscope. An instrument for viewing lantern slides, similar to the Alethoscope and Pantoscope (q.v.).
Latent Image. See Image, Latent.
Latent Light. Many years ago Niepce de St. Victor found that if paper saturated with nitrate of uranium was exposed to sunlight and enclosed in an opaque tube or case for several months, it would still give off radiations capable of affecting a photographically sensitive surface. Plain white paper behaved somewhat similarly. (See Luminous Paint, and Radiography.)
Lavender Rays. The faintly luminous rays at the extreme end of the visible spectrum are sometimes so called.
Lead, Acetate of, (Ger., Essigsaures Blei; Fr., Acetate de plomb; Ital., Acetato di piombo). Pb(H3C202)2,3H20 = 379. Synonyms : Plumbic Acetate, Sugar of Lead. Made by dissolving litharge in an excess of acetic acid and subsequent purification