THE KALLITYPE PRINTING PROCESS.
The kallitype printing process was invented and patented by Dr. Nichol of England, professor of chemistry in Mason College. The name "kallitype" is often confounded with "calotype," the name which Talbot gave to his paper negative process, patented in 1841. Both names are derived from the same Greek words meaning "beautiful picture." Kallitype paper is coated with two iron salts—ferric oxalate and ferric nitrate—and with silver oxalate and silver nitrate. The action of light on the ferric oxalate is to reduce it to ferrous oxalate. This paper is not a printing-out paper, but must be developed. A developing solution is prepared as follows:
| Rochelle-salt | 1 | oz. |
| Borax | ¾ | oz. |
| Water (filtered) | 10 | oz. |
Make up a solution of 20 grains of bichromate of potash and 1 oz. of water, and another solution of four drachms of ammonia to 1 quart of water. When ready to develop the prints, add ten drops of the bichromate of potash to the developer. Place the prints in the developer face down, taking care that no air-bubbles form on the surface of the paper. When the paper is thoroughly saturated it can be turned face up. Leave the prints in the developing bath for at least twenty minutes, then, without washing, place them in the dish containing some of the ammonia and water. This is the fixing bath. Leave them in this bath for about ten minutes, then turn out and cover with fresh ammonia and water. Let them remain ten minutes in this second fixing bath, wash and dry.
The prints made on this paper closely resemble platinotype prints, but the process is much cheaper. If purplish tones are desired, make up a developing bath with a quarter-ounce of borax instead of three-quarters. The developer containing the three-quarter ounce of borax gives black tones. The bichromate of potash added to the developing solution keeps the prints clean and increases contrast.
Sir Knight Bert A. Porter, Strong, Me., asks if directions have ever been given for copying pictures and mailing interior views; if a brass plate can be prepared so that a picture may be printed on it; and the best kind of paper to use to obtain clear lights. Directions for making interior views will be found in Nos. 805, 806. If one has not a copying-stand, the best substitute will be a board the width of the camera bed, and about five feet in length. At one end fasten a piece of board large enough to allow the picture being tacked to it, having it at exactly right angles with the long board. The camera is then attached to the board at the best point for making the picture. This simple method of arranging the picture and camera does away with the trouble of adjusting the camera and picture so that the lines will be parallel. Use orthochromatic plates if the picture is colored, but any good plate will do if the picture is black and white. Use a slow plate. Pictures may be made on wood, leather, porcelain, and textile fabrics, but pictures on metal are not successful by the ordinary process. Any good aristo-paper will give clear whites if properly toned and washed. Sir Knight Bert would like to correspond with any one who wishes to purchase a 5 by 8 camera.
