661. Repairing Cracked And Broken Negatives

Repairing Cracked And Broken Negatives. The breaking or cracking of a negative is not of infrequent occurrence even in the best of well-regulated studios, and usually it is the negative most wanted that gets damaged. However, a cracked negative, or even a badly broken one, is not beyond repair. There are various methods in vogue for preparing such damaged negatives for the printing-room, but we will only mention those that are of most general service.

662. Negative Cracked, But Film Not Broken

Negative Cracked, But Film Not Broken. With such a negative the best method is to lay the cracked negative very carefully on a clean sheet of glass made from an old negative, and to bind them together with sticking tape around the edges. Then, when printing, proceed to place the negative and paper as usual in the printing-frame, in the corners of which tacks have been driven, to which strings are attached. The ends of the strings are tied together at any distance above the negative found suitable, and the whole suspended from a cord fastened in the window. Spin the printing-frame and keep it spinning during the printing of the paper. In this way all parts of the cracked glass will be presented evenly to the light, and no sign of the crack will show in the finished print. Printing should be done in diffused light.

663. Another method: A deep cardboard, or wooden, box can be used, the printing-frame being laid on the bottom of the box, which is placed in a window in diffused light. Printing will take much longer than ordinarily, but very little signs of the crack will be visible in the print.

664. If the negative is valuable and its use may be of frequent occurrence, the film (provided it is not broken)

can be transferred to another sheet of glass entirely. To do this, first harden the negative in a 10% Formalin bath, so that the film will not expand in the subsequent process; then place some clean water in a tray, to which is added a few drops per ounce of Hydrofluoric Acid. With the point of a sharp knife cut around the film about an eighth of an inch from the edge, and then place the negative in the Hydrofluoric bath. The film will gradually come away from the glass. Keep the tray rocking slowly until the film is entirely removed; then pour away the acid bath and wash the film with clean water.

665. Next introduce into the tray a carefully cleaned piece of glass - an old, cleaned negative will do - and bring it under the film. Using a soft brush, press out all bubbles that may adhere to the glass under the film; then withdraw glass and film, holding the film to the glass at one end by the fingers. Unless the film has been hardened too much it will adhere to the glass when dry. Stand up on end to drain and dry. An ebonite or celluloid tray should be used, as Hydrofluoric Acid attacks glass or porcelain.

666. Glass And Film Both Broken

Glass And Film Both Broken. Another method more frequently employed, and one that may be applied successfully even where the glass and film are both broken, is to attach the negative to a plain piece of glass, with binding tape, place it in the printing-frame and make a transparency by contact, holding the frame containing the negative and dry plate at such an angle to the light as to show as little of the crack as possible. The correct angle you can ascertain by first holding the negative to the light before placing the sensitive plate in the printing-frame. You will observe that when holding the negative at a certain angle the crack, or cracks, show less than they do when holding at other angles. After ascertaining the correct angle whereby the least appearance of the crack will show, place the sensitized plate on the negative in the printing-frame, hold it at the right angle, and expose by artificial light, holding the frame at least two feet from the source of illumination. (See Lantern-slide Making, Volume V.)

With the transparency made, whatever cracks are visible should be removed in the transparency. The transparent lines are removed with a BB retouching lead, and all opaque lines are removed with the etching knife. By this means all appearance of cracks that were visible in the negative may be almost entirely removed in the transparency. With this done make a negative from the transparency by contact. The negative should appear free from any marks whatever. If, however, any parts of the crack still appear, you may again apply similar work upon the negative, using the pencil for transparent lines and the etching knife for the more opaque ones, thus entirely eliminating all cracks and resulting in a perfect negative.