Sometimes one is so unfortunate as to break a negative which cannot well be replaced. The amateur who understands little about photographic work is, in such a case, quite likely to think that the negative is ruined, and throw it away; but unless it has been broken in many pieces it can be repaired so that one can get as good a print from it as before it was broken.
If there is one clear break across the glass, but not through the film, place the negative in the printing frame, pushing the broken edges closely together, holding them while adjusting the sensitive paper. Fasten in the printing frame, and print in a diffused light—that is, not in the direct rays of the sun. Place the negative at such an angle with the light that the crack across the glass shall not make a shadow.
If there are several cracks in the glass, but not in the film, put the negative in the printing frame, supporting it by a piece of plain glass; tie cords to the printing frame so that it may be suspended by them; hang the frame from some projection where it will not hit anything, and keep it revolving during the printing process. The plate moving all the time, the cracks in the glass do not cast a shadow long enough in one place to make any impression on the sensitive paper. If one cannot arrange the frame in this way, it may be placed at the bottom of a large deep box without a cover, and left to print.
If the film is broken as well as the glass, take a piece of plain glass the size of the negative—a spoiled plate is just the thing—lay the broken pieces on this plain glass, taking care that the picture lines of the negative are true, and bind the edges of the glass and negative together with strips of gummed paper. When the strips are dry, varnish the film with negative varnish. It is better to purchase the varnish ready prepared than to attempt to fix it one's self.
If the negative is badly broken, but not splintered, apply Canada balsam with a toothpick to the edges of the broken parts, and press them firmly together, keeping the negative on a flat surface during the process, a glass plate a little larger than the negative being the best thing to use. When the balsam is thoroughly dry, flow the negative with varnish, and as soon as it begins to set cover it with a piece of glass the size of the negative. When dry, bind the edges together with strips as before directed. If the negative is very badly broken, it should be enclosed between two pieces of plain glass, putting on the second in the same manner, after the first is dry. Bind the three together.
An excellent paste for binding negatives and lantern slides is made of rice flour. Mix rice flour with water till it is smooth and free from lumps. Set the dish containing it into another of hot water, and boil till it becomes thick and semi-transparent, stirring it all the time. When done it should be about the consistency of laundry starch made for collars and cuffs. This paste is very strong—in fact, almost as durable as cement. If a few drops of carbolic acid are added to it, it will keep for some time. The bottle should be tightly corked when not in use.
If the film has not been broken it can be removed from the glass in the same way that films are stripped, and transferred to another clean plate.
For very valuable negatives it is a good plan to make a paper negative, in case of accident to the glass one. A paper negative is made by taking a good print of the negative and waxing it according to directions given in No. 782 "answers to queries." Make a print from this waxed positive, supporting the paper while in the printing frame by a sheet of plain glass. Tone and fix this print, which will be a negative. Wax it, and if you are so unfortunate as to break the original, you will still have the paper copy, which can be used in its place.
For negatives that can be replaced it is not wise to spend the time in repairing them if broken, but it sometimes happens that a valuable one is broken which cannot be duplicated, and with careful handling it can be made "as good as new."
Sir Knight Harry T. Luther, New York, asks what causes his negatives to turn yellow, and if there is any remedy for it. The reason why negatives turn yellow is usually because they have not been washed long enough. They should be washed in running water an hour. If running water is not convenient soak the plate for two hours, changing the water several times. The yellow stains may sometimes be removed by soaking the negative for a short time in a solution of one ounce sulphite of soda and nine ounces water, to which a few drops of sulphuric acid have been added. Sir Harry also asks what toning solution to use with the plain paper described in Nos. 796 and 803. The combined toning solution used for aristo paper is the best solution for the plain paper. It works quickly, and gives soft clear tones.