To make violet tones the paper is first sensitized in the same way described for making red prints. Make a solution of 96 grs. of nitrate of uranium and 4 oz. of water. Put this solution in a shallow tray, such as is used for toning, and float the prepared photographic paper on this for twenty seconds; drain carefully, and pin up to dry in a dark room. If dried by artificial heat the paper is made more sensitive and prints more quickly.
As soon as the paper is dry wrap it in post-office paper, and then in black needle-paper—such as sensitive papers are wrapped in—and lay it away in a drawer or covered box till wanted. This paper may be prepared several days before using, but should not be kept too long.
To print, place in the printing-frame and expose to light. If the negative is thin, three minutes in bright sunlight or one hour in the shade or a very dull day will be necessary for printing, and if a strong negative, ten minutes in bright sunlight or two hours in the shade will be necessary.
Have ready prepared a solution of 8 grs. of chloride of gold and 4 oz. of water. As soon as the print is taken from the frame wash it for twenty-five or thirty seconds in hot water (120° Fahr.), and place face up in a toning-tray, and flood the print with the chloride-of-gold solution. The print does not show when it is taken from the frame, but is developed with the chloride-of-gold solution. When the detail is well out, and the color a rich violet, take from the tray and wash in running water or in several changes of water, till none of the coloring matter shows in the water. Pin by the corners on a flat board, and set the board in an upright position till the prints are dry.
These violet prints are very attractive for certain kinds of work. Flower studies, especially those of single flowers, make novel prints. A set of four different colored prints might be made and used as decorations for a calendar. Mount the prints on square sheets of heavy drawing or Bristol board, and on each sheet place a three months' calendar. These calendars may be obtained at any stationery-store. The cards may be further decorated by tracing fine gilt lines round the picture and calendar leaves. An appropriate motto may also be added to each sheet.
Of course the first of the year has already passed, and it may seem out of season for suggestions as to making calendars, but one of the prettiest birthday gifts to a friend is a calendar beginning with the day of the month which marks his or her birthday. Such a calendar is very convenient, for it laps over into the coming year, which is sometimes a great advantage. Instead of mounting the prints directly on the card, an opening may be cut in the card and the picture placed behind it, as described in "Tinted Papers," No. 1. If this is done, a thinner piece of card-board should be pasted on the back, not only as a finish, but as a protection to the picture.
Blue prints may be toned to a dark violet by first printing, washing them in clear water, and then flowing them with a solution of 1 part potassium hydrate in 300 parts of water, and again with a solution of 4½ oz. of alcohol (90 per cent.), 7½ oz. distilled water, 1 oz. gallic acid. This gives the prints a dark purple or violet color, not so pleasing as that made by the process just given, but, if not printed a too deep blue in the first place, look very well.
Tinted papers—with the exception of carbon papers and blue prints—are not found in the market, but must be prepared by the amateur.
Mr. Emil Dæche, Patron, of Jersey City, New Jersey, gives the formula which he uses for toning aristo paper whereby he obtains fine chocolate tones, and asks if prints made by this process will be permanent. The prints, if well washed, ought to be permanent, and not turn yellow. The reason why prints turn yellow after having been made some time is not so much the toning process as the fault of the paper. Aristo prints are not as permanent as albumen, bromide, or platinotype prints, or even those made on plain salted paper. Improvements are being made in aristo papers, and they are now of much better keeping quality than those first put on the market. If Mr. Dæche will kindly send a more detailed account of the process which he uses, we should be glad to publish it for the benefit of the members of the Camera Club.