Half-frame is a negative format of 18 x 24mm. Images are recorded on a vertical axis on standard 35mm film, thus giving 72 half-frame images on film designed for 36 exposures. Some early cameras produced negatives of this size. Half-silvered mirror is a glass sheet evenly coated with a substance which transmits part of the light incident on it and reflects the remainder. Used for beam splitting devices in holography , and for front projection.
Halftone is a mechanical process for printing continuous tone images in ink.
Halogens is a collective term for the elements chlorine, bromine and iodine, which are combined with silver to produce the light sensitive crystals used as the basis for photographic emulsions. Hand coloring is a process of applying color tints, in the form of paint, to a photographic image to create or enhance the color effect. Hanger is a frame for holding sheet film for processing. Hard defines a scene, negative or print with high contrast. Hardeners are chemicals often used with a fixing bath to strengthen the physical characteristics of an emulsion.