A chemical term used to denote the collection of various compounds, together with their quantities, which are required to make up certain solutions.


Plural of Formula


The changing of a liquid to a solid by the influence of cold.

French Chalk

(See Chalk, French.)


The wrinkling or detachment of a film around the edges of plates or paper. Very often happens in hot weather or when using too much alkali in the developer.

Rising and Falling Front

A term signifying that the frontboard to which the lens is attached may be raised or lowered in order to secure more sky or foreground without altering the position of the body of the camera.

Swing Front

(See Bed, Swing.)

Full Aperture

The largest available opening of a lens.

Fuller's Earth

A clay usually of a greenish tint. Absorbs grease and is useful for cleaning purposes.


The process of exposing plates or paper to the fumes of a chemical in order to make them sensitive.


A conical-shaped vessel terminating at the smallest end in a spout. Used for pouring a liquid into a vessel having a small opening. Also for filtering liquids through filter paper.


The act of melting or making a solid liquid by means of heat.

Gallic Acid

(See Acid Gallic.)


An English measure of capacity. It is equal to four quarts. Gamboge.

A bright-yellow, resinous gum. Soluble in both water and alcohol. Used in blocking out negatives. (See Dodging in Printing.)


A vaporous substance not condensed into liquid form at ordinary temperature.

Gaslight Paper

A slow bromide paper which can be handled in ordinary gaslight.


A pure, brittle, transparent, tasteless glue. Swells in cold water, but will not dissolve until heated. The melting point varies with the quality of the gelatin. One of the most useful materials employed in photography. Practically all plates are coated with an emulsion whose basis is gelatin; also used in the emulsions on various sensitive papers.

Genre Work

A term used with reference to the representation of some phase of common life, such as a rural or village scene. It of necessity must include one or more human figures. It is entirely foreign to portraiture as commonly considered, for the subject should be occupied with some familiar work. In brief it is producing a picture that tells a story.


A hard, brittle, transparent substance used as a support for dry plate emulsions, in manufacturing of lenses, etc.

Glass Cement

Heat equal parts of gutta percha and shellac on a sand-bath until melted. This cement can be used for cementing glass to glass or to metal. Use hot; also have glass or metal hot.