Diffusion of Liquids

The gradual mixing or diffusing of one liquid into the other when placed in contact with each other.

Litmus Paper

(See Paper, Litmus.)

Liter

A Metric measure of volume.

Long Focus

The term which signifies that the distance between the lens and sensitive plate is greater for a particular size negative than a lens of short focus. Such a lens embraces a narrow angle. (See Angle of View.)

Lumiere Process

A process of color work named after the inventors; also called the AUTOCHROME PROCESS.

Lunar Caustic

(See Silver Nitrate.)

Lunar Photography

Photographing the surface of the moon.

Photographing Machinery

Various methods- of photographing machinery are taken up in the text. The following formula produces an excellent paint for dulling bright surfaces:

White Lead (dry)..................

2 1/2 lbs.

Lampblack................................................

1 to 3 ozs.

God Size...................................................

1/2 pt.

Turpentine.................................................

3/4 pt.

The amount of lampblack used depends upon the subject as well as the lighting. Apply the paint in the ordinary manner.

After the exposure is made the paint may be removed with waste or rags saturated in turpentine.

Magazine Camera

(See Camera, Magazine.)

Magic Lantern

(See Optical Lantern.)

Magnesium

Mg

Lustrous, silver-white, malleable, moderately hard metal; burns with brilliant white light. Used in powder form for artificial illumination.

Magnesium Chloride

MgCl2 + 6H2O.

Colorless, deliquescent, bitter crystals. Soluble in water; partly soluble in alcohol. Keep in well stoppered bottle. Used, sometimes in the manufacture of gelatino-chloride crystals.

Magnesium Flashlamp

A lamp specially constructed for the igniting of magnesium powder for artificial illumination. Extreme care must be taken not to place flashlight compounds in a lamp of this kind, as a dangerous explosion will result.

Magnesium Iodide

Mgl2 + 8H2O.

Deliquescent, crystal powder. Decomposes in solution. Occasionally used in collodion.

Magnesium Light

An artificial light produced by burning magnesium ribbon or powder. Rich chemical rays.

Magnesium Sulphate

MgSO4 + 7H2O. Epsom Salts; or Bitter Salt.

Small, colorless, prismatic crystals; odorless; bitter, saline taste. Soluble in 1.5 parts cold water, 0.3 parts boiling water; insoluble in alcohol. Its principal photographic use is as a constituent of flashlight compounds.