This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
(a) The shades or tints between the highest points of light and the deepest shadows of an image; (b) a copper or zinc plate on which is made a reproduction of a photograph, the half-tones being represented by fine dots. Used for illustrating books, newspapers, etc., the reproduction being in one color of ink.
(See Salts, Haloid.)
A name given to the salts formed by the combination of a metal with a halogen element. For instance, the union of chlorine with silver forms silver chloride and is, therefore, a haloid salt of silver.
Any arrangement or combination of relative parts or elements that is consistent or is aesthetically pleasing; agreement of particulars according to some standard of consistency or to aesthetic judgment; an accordant, agreeable, or suitable conjunction or assemblage of details; concord; congruity. Harmony is to be distinguished from symmetry: thus, in a symmetrical building two opposite wings are exactly identical, though usually with the architectural members in reverse order, while in a harmonious building the two wings need not be identical in a single detail, if they balance each other so as to form, taken together, a pleasing and consistent whole.
A Metric weight or measure containing 100 grammes.
A Metric measure of capacity for liquids.
A Metric measure of length.
(See Lens, Heliar.)
A modification of the collotype process.
An art term denoting portions of a picture which have received the greatest amount of light; i. e., that part of the subject on which the light has been concentrated. In the negative these portions are the densest or most opaque.
A very common form of composition, based upon the curved form of the letter S.
A case in which the sensitive plate is carried. After the image has been focused on the ground-glass the plate-holder is inserted in position, the slide which protected the surface of the sensitive plate is withdrawn, and the exposure made, after which the slide is replaced and the holder withdrawn SINGLE plate-holders accomodate only one plate, while in the DOUBLE plate-holder two sensitive plates may be placed.