The Dictionary Of Photography

A True Historic Record Of The Art & Practice Of Photography 100 Years Ago.

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Magic Pictures
Magnesium
Exa?nple. Size of picture desired 15 feet; focus of lens 8 ins.
3. Having a given focus lens, and given distance between lantern and screen, required to know diameter of picture that will be produced. Multiply the distance between lantern and screen by the opening of the slide, and divide by the focus of the lens.
Example. Lens of 9-in. focus, distance between lantern and screen 40 feet, required size of disc.
In connection with the Magic Lantern the following articles may be consulted: - Table of illuminants under Light, Oxy-
HYDROGEN LlGHT, ACETYLENE, CONDENSER, APHENGOSCOPE J and
as regards slides for the lanterns, see Line Drawings, to Copy, Hydroquinone, Emulsion, Albumen Process, and Lanternoscope. On p. 181, et. seq. (Development), will be found some instructions for making lantern slides on com-mercial plates. (For description of the magic-lantern used in pro-jecting the so-called living photographs, see Cinematograph.)
Magic Pictures. These are prepared by a process discovered by Sir John Herschel. Print as usual on albumenised paper, fix without toning, and wash thoroughly; immerse the prints in a saturated solution of perchloride of mercury until the image is thoroughly bleached and disappears, wash and dry. To make these invisible images appear at the word of command, as if by magic, place over one a wetted sheet of blotting paper, which has been previously soaked in a saturated solution of hypo-sulphite of soda, and press the hand upon them, when the image will start up with more than its original vigour.
Maglip, or Meg'lip. An artist's material, made by mixing boiled linseed oil with mastic varnish. It is used for thinning oil colours and for glazing on delicate tints on finished oil-paintings.
Magnesium . (Ger., Magnesium; Fr., Magnesium; Ital., Magnesio). Mg = 24. Occurs in large quantities as dolomite
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