Haloid Salts

The term haloid salts is applied to four elementary chemicals, which form a group whose chemical properties are more closely connected by their similarity than those of any other group of elements. These four haloid salts, or as they are usually termed halogens, resemble sea-salt in their composition, and are CHLORINE, BROMINE, IODINE AND FLUORINE.

Salts of Tartar

(See Potassium Carbonate.)

Sandarac

Gum Sandarac. Brittle, elongated, light-yellow tears; translucent with vitreous fractures; crumbles to powder when masticated; inflammable. Soluble in alcohol, ether, acetone and in hot caustic alkalies; partly soluble in chloroform, volatile oils, oil of turpentine. Used in making varnishes.

Printing on Satin

(See Silk, Printing on.)

Saturated Solution

(See Solution, Saturated.)

Saxe Paper

(See Paper, Saxe.)

Schlippe's Salt

(See Sodium Sulphantimonate.)

Scratches

Scratches on negative films often occur, and many times they may be retouched by using either a soft pencil or India ink on a brush. In order to avoid the negative being scratched it should be coated with a proper negative varnish. (See Varnish.)

Diffusing Screen

A screen made of cheesecloth or thin muslin placed between the source of illumination and the subject, to soften or assist in controlling the light which falls upon the subject.

Focusing Screen

(See Focusing Screen.)

Ray Screen

(See Color Filter.)

Reflecting Screen

A screen usually consisting of a frame on which is stretched white cloth. Used in portraiture to reflect light into, and illuminate, the shadows.

Sealing Wax

When chemicals are to be kept in bottles for any period of time, the bottles should be filled full with the solution and the cork or rubber stopper inserted, and then sealed with sealing wax. The sealing wax which may be obtained from any stationery store will answer the purpose. RED SEALING WAX can be made by melting four ounces of bleached shellac with one ounce of Venice turpentine and three ounces of Chinese vermillion. GOLDEN SEALING WAX is made by using powdered yellow mica instead of vermillion. When BLACK WAX is desired ivory black may be substituted in place of the vermillion.

Sector Shutter

(See Shutter, Sector.)

Self-Toning Paper

(See Paper, Self-Toning.)

Semi-Opaque,

Half opaque and half transparent. Semi-Transparent.

Partly transparent. Sensitize

The process or the act of making a substance sensitive or capable of being easily affected by actinic light.

Sensitized Paper

(See Paper, Sensitized.)

Sensitizer

A substance added or applied to the emulsion to increase or alter its sensitiveness to light.

Sensitizing

Making sensitive to light, or the operation of coating with or immersing in a sensitizing bath, solution, or emulsion.