NO. 4.—HOW TO MAKE GREEN TONES.
Green prints may be made by first making a red print, and then, by the use of nitrate of cobalt, changing the red tone to a brilliant green. The process for making red prints is fully described in No. 850 of the Round Table, but we repeat the formula, referring the amateur to the paper on red prints for fuller details.
Sensitize photographic paper by floating it on a solution made of 96 grs. of nitrate of uranium dissolved in 8 oz. of distilled water. Dry by a gentle heat, and print. This is not a printing-out paper, but the picture is brought out by development. A strong negative requires ten minutes in bright sunlight and two hours in the shade. Remove the print from the frame, and place at once in a dish of hot water for 30 seconds (120° Fahr.). Drain off the water, and lay the print face up in a toning-tray, and flood with a solution made of 40 grs. of red prussiate of potash and 4 oz. of distilled water. Keep the tray in motion so that all parts of the print may be equally affected by the developer. In a few minutes the picture will begin to appear, and will develop up a beautiful red color. Wash this print in several changes of water till no more color runs from it and the washing water is clear.
Have ready a ten-per-cent. solution of nitrate of cobalt. Place the red print in this without drying, leave it in for one minute, remove, and, without washing, dry by a fire. The red print will turn to a beautiful green; the more intense the heat used in drying the more brilliant will be the green color. This print is not permanent, but must be made so by immersing in a fixing solution prepared as follows:
| Distilled Water | 4 | oz. |
| Sulphate of Iron | 80 | grs. |
| Sulphuric Acid | 4 | scruples. |
Have this solution made up at the dealer in photographic supplies, as the sulphuric acid is a dangerous acid to handle. The small quantity in the solution will do no harm, though it is best to use rubber fingertips when handling all known poisonous chemicals. Place the print in this fixing solution for 30 seconds, pass it through three or four changes of water, and dry by the fire. Landscapes printed on green tinted paper make a pleasing change from the brown and black tones generally used.
Sir Knight W. F. Blatchley asks what kind of sensitized paper to use for pictures which are to be reproduced in periodicals. Any printing paper, with the exception of blue prints, may be used; but the black and white tones are preferred to the reddish browns.
Sir Knight Le Roy Thompson asks what other color beside red and violet may be produced with nitrate of uranium. Green, blue-black, chestnut-brown, copper color, and several other tints may be made by different toning solutions or treatments of the print. The processes will be described in early numbers of the Round Table.
Sir Knight Thomas S. Winston, Box 65, Albertville, La., says that he has some curios, consisting of turtle shells, water moss, water celery, wild boar's tusks, etc., and a collection of about one thousand stamps, which he would like to exchange for a Pocket Kodak or a Kombi Camera.
Sir Knight Lawrence Fraley sends the following formula for developing bromide paper: Water (filtered), 20 oz.; carbonate of soda, 300 grs.; sulphite of soda, 500 grs.; hydrochinon, 30 grs.; metol, 30 grs. Sir Knight Lawrence says that he has used this developer, and finds that one can make a much shorter exposure and obtain clear whites and fine detail in shadows. This developer works equally well with dry plates. Sir Lawrence has the thanks of the club for his formula.
Lesley Ashburner asks what makes prints gray; the sizes and prices of transferrotype and bromide paper; a formula for toning solution; and in what number it gives directions for enlargements. The reason prints assume a gray color is because they are left too long in the toning solution, or the toning solution is not fresh. Bromide and transferrotype paper may be bought in any size desired; 4 by 5 costs 50 cents per dozen, and 5 by 7 costs 65 cents per dozen for both papers. A formula for toning solution may be found in No. 825. A formula for toning solution comes with every package of sensitive paper, and may always be relied on to produce good results. Several toning solutions will be given in an early number of the Camera Club. The number giving directions for enlarging is No. 801 of the Round Table, and the article is entitled "Bromide Enlargements."