Stereoscope

An instrument for viewing stereoscopic views.

Stereoscopic Views

Two views made from slightly different view-points of one particular subject and mounted side by side on one mount. Generally made with two lenses in the one camera, with the lenses mounted 3 1/4 inches apart. When viewed through a stereoscope the appearance is that of the natural relief as seen when viewing the subject from the same view-point as that from which the view was made.

Stigmatic Lens

(See Lens, Stigmatic.)

Still

An apparatus for distilling water or other liquids.

Stock Solution

(See Solution, Stock.)

Stopper

Bottles containing acids and strong alkaline solutions should be fitted with glass stoppers in preference to rubber or cork. Glass stoppers can be made to fit in the neck of bottles by grinding them in with a little fine emery powder paste. Many times glass stoppers will stick tightly in the bottle. (See Bottle Stoppers, To Loosen, for methods of removing stoppers from bottles.)

Stopping Down

Decreasing the size of the aperture of a lens by inserting a smaller stop or using a smaller diaphragm.

Stripping Film

Removing a gelatin or collodion film from its support. (See Acid Hydrofluoric.)

Studio

Properly speaking, the room in which the photographer makes portraits, erroneously called the operating-room. The length of the studio must be in accordance with the length of the focus of the lens employed. When selecting lenses the focal length must be that which will give the best results in that particular room. (See Skylight.)

Sub-Chloride of Silver

(See Silver Sub-Chloride.)

Sub-Iodide of Silver

(See Silver Sub-Iodide.)

Corrosive Sublimate

(See Mercuric Chloride.)

Sublimation

(See Distillation.)

Substratum

An underlying coat or layer. The substratum coating is usually a term applied to the first coating given plates and papers.

This coating is applied in order to make the emulsion adhere evenly to the surface of the glass or paper.

Sugar of Lead

(See Lead Acetate.)

Sulphate of Baryta

(See Barium Sulphate.)

Sulphate of Calcium

(See Calcium Sulphate.)

Sulphide of Ammonium. (See Ammonium Sulphide.)

Sulphide of Potash

(See Potassium Sulphide.)

Sulphide Toning

A method of producing sepia tones on bromide prints, lantern-slides, etc.

Sulphite of Sodium

(See Sodium Sulphite.)

Tests for Sulphites

Nitrate of silver added to a solution containing sulphites will give a white precipitate. When ferric chloride is added to solutions containing sulphites a blood-red color will result.

Sulphocarbonic Acid

(See Carbon Disulphide.)

Sulphuretted Hydrogen

An inflammable gas. Has a very disagreeable smell. Soluble slightly in water; more soluble in ammonia, soda and potash. Used to precipitate silver sulphide from fixing baths containing alum.