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.
Leather-brown or yellowish-green pieces. Deliquescent in moist air. Soluble in 2 parts of water, with but a slight residue. Gives an alkaline yellowish-green solution. Used to precipitate black silver sulphide from old fixing baths.
KSCN. Potassium Sulphocyanate. Colorless, prismatic crystals. Deliquescent in the air. Easily soluble in water and in alcohol. Used in various toning processes. Sometimes employed as a developer in the carbon process, owing to its power of dissolving gelatin. EXTREMELY POISONOUS.
Usually a written statement of the medicines or remedies to be used by the patient and the manner of using them.
A chemical used to preserve the keeping qualities of sensitized papers and plates, also solutions. Ex. Sodium sulphite or potassium metabisulphite are used in pyro developer to preserve the pyro, i. e., to keep the developer from oxidizing too rapidly during the process of development, and to preserve the solution before use.
(See Axis, Principal.)
VI. (See Focus, Principal.)
A knife or instrument of any kind employed for trimming prints.
The term applied to the method of obtaining positive pictures from the negative, on paper, or any other suitable material.
The extent to which printing must be carried in order that the resultant print may be of the proper strength.
(See Dodging in Printing.)
A frame in which is placed the negative, and on top of this the sensitive surface of the printing paper, which latter is pressed into close contact with the negative, when it is ready for exposure to light.
A term designating the addition of clouds, figures, etc., to a print from another negative, and which has spaces specially masked out for their insertion.
A term applied to any printing process in which the image becomes visible during the process of printing, being entirely produced by the action of light.