Magazine article Journal of Film Preservation

Wrinkled Emulsion Layer: Restoration by Transplanting to the Negative

Magazine article Journal of Film Preservation

Wrinkled Emulsion Layer: Restoration by Transplanting to the Negative

Article excerpt

When photographic material is placed in an environment where the relative humidity is unusually high, its emulsion layer may absorb a large quantity of moisture and swell excessively; its support may shrink from decomposition; or the plastics may separate out unevenly in the form of crystals and remain in the interface between emulsion layer and support. All of the above may cause a wrinkling of the emulsion layer. Macroscopically there appear peaks and valleys. Such a negative is generally no longer capable of printing a photograph.

Now we introduce a method of clearing up the wrinkles on a photographic negative and of restoring its original appearance. Here we must point out that the following method is effective only for cut negative film that has been stored over a long period in an unsealed state. For cine film materials and cine film copies stored in metal containers, or for negatives stored in a sealed state, the following method is not generally effective. This is because, when an image material is stored in a sealed state for a long period, the gelatin in its emulsion layer is attacked by the decomposition products of the support and becomes seriously degraded. Then the emulsion layer turns readily soluble in both acidic and alkaline solutions. Thus the loss may be irretrievable.

Restoration of cellulose nitrate negative

Whether a wrinkled image layer of nitrocellulose-base cut negative film can be successfully transplanted or not depends largely on whether the gelatin layer has maintained its toughness. The best method of judging this is to moisten the edge of a wrinkled emulsion layer with a piece of damp absorbent cotton, and to observe whether or not the gelatin has dissolved. If the emulsion layer only swells, but does not dissolve, and maintains its toughness, then it can be transplanted successfully.

a. Preparations

1. Take the wrinkled negative to print an enlargement. In cases where the attempt of transplantation has failed, then this photograph could be preserved as a substitute of the original negative.

2. Preparations of accepting support. From a subbed cellulose acetate support cut out a piece, a little larger than the wrinkled negative, to use as the accepting support. If such a material is not available, take a fresh black-and-white negative, have it fully fixed, washed and dried; it is then ready for use.

3. Compound the image layer separation solution.

4. Instruments for transplantation: Vessel for negative transplantation solution, scissors, working table with transmitted light source, etc.

b. Transplantation of image layer

1. Pour the image layer separation solution into a vessel 8-10cm deep, maintaining the solution temperature at 15-18°. A high temperature is apt to cause the dissolution of the emulsion layer, while a low temperature is unfavourable for the separation of image layer from the support.

2. Cut off c.1-2mm from the edges of the negative of which the image layer shall be transplanted, in order to prevent the possibility of adhesion between the support and its upper and lower gelatin layers.

3. Place the negative, whose emulsion layer has wrinkled, into the separation solution, constantly observing the changes of image layer. Whenever the edges of image layer are found wrinkling, twist gently with the fingers so as to separate image layer from subbed layer. When there appears a greater part of image layer separated, hold this with thumb and forefinger and carefully remove from subbed layer as quickly as possible, taking care not to remove from the separation solution. Leave the unfolded protective layer floating face-upward in the solution.

4. Then remove image layer from the separation solution with a bottom-upward accepting support, place onto the working table, spread out smoothly with a Chinese writing brush, ease out air-bubbles and moisture, and then dry the newly-formed film in the air. The whole transplantation work is now completed. …

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