This section is from the "Studio light a magazine of information for the profession 1915" book, by Sara F. T. Price. Also see Amazon: Studio light a magazine of information for the profession 1915.
A few years ago the fastest plate was slow in comparison with the fast plate of to-day. Likewise the dark room light of a few years ago may be safe enough for ordinary plates but not safe enough for a plate as sensitive as the Seed Graflex.Then again, the light may be safe enough for even the Seed Graflex and become unsafe even for slower plates, when it has been in use for some time.
When you are looking for the cause of fog, test your dark room light first thing and you may not have to look further. Many dark room lights consist of a wooden box with an electric globe inside and a piece of ruby paper between glass covering the open side. Even the glass is sometimes omitted.
Such an arrangement with no means of ventilation causes the paper or fabric to deteriorate from the heat as well as the light. Use both red and orange paper or fabric and renew it when there is any indication of a change in color.Also have the paper or fabric between glasses so that it will not be splashed with water or chemicals and become unsafe in spots. Lamps on the order of the Wratten Safelight Lamp in which only reflected light reaches the colored paper, fabric or glass are safest, but if direct light is used, even ruby glass will be found unreliable when used alone. The ordinary grade of ruby glass, though quite dark, may pass a considerable amount of actinic light unless a sheet of yellow glass or paper is used back of it. And if this does not prove safe when tested with a fast plate, use a sheet of Post Office paper or a Seed Dark Room Light Cover between the glasses. The Seed Dark Room Light Covers are furnished free of charge. Even with a light which is reasonably safe, plate holders should be loaded on a shelf opposite the light and as much in shadow as possible. The idea of the dark room light is to distinguish objects in the room and to examine negatives when development is well under way. Careless handling of extremely sensitive dry plates by any dark room light is unnecessary and very likely to cause a slight veil of fog over the entire negative.
Artura Aegis for uniform sepias of distinctive tone.
SEED 30 NEGATIVE, ANGELO PLATINUM PRINT
By The Hoover Art Co. Los Angeles, Calif.