Photographic negative collections present unique problems to institutions and collectors. Glass-plate negatives can break easily, cellulose nitrate and the various cellulose acetate negatives will self-destruct over time, and negatives are generally difficult to read and to access. The duplication of negatives is one preservation option available to help alleviate the problems. Duplication can preserve a deteriorated image, protect a negative from excessive handling, or improve access to a collection. However, duplication has limitations: each successive generation of an image loses quality and detail. Therefore it is critical that duplicate negatives be printed on stable materials and have the highest quality image reproduction. Duplicate negatives should be on modern polyester film and duplicates should have, as close as possible, the same density range and the same amount of detail as the originals.
Duplication of a negative collection is a complex and expensive process. Many decisions need to be made before a duplication project is undertaken. The information below will provide some guidance for those considering the duplication of historical negatives.
Prints and Copy Negatives
The simplest way to duplicate negatives is to make a print and then to photograph the print using a large-format camera (4" x 5" or larger) to produce a copy negative. The advantages of this method are cost and convenience. Most museum darkrooms or local photo labs should be able to do the work with little or no investment in equipment. Further savings may be achieved by using already existing prints for copying. Where no original negatives exist, copying existing prints is the only available option. The disadvantage of this system is loss of detail in both the print and the copy negative. A print always has detail loss and a compressed tonal range when compared to the original negative, and further detail is lost when the copy negative is made.
Direct Duplicate Negatives
Eastman Kodak Professional Black & White Duplicating Film #SO-339 is designed for directly duplicating negatives. This is a one-step process yielding a negative from a negative. Duplicating film has high resolution, minimizing loss of image detail during copying. Also contrast can be manipulated during duplication to salvage some problem negatives. However, since the film is blue sensitive, minimizing staining can be problematic. This film can be difficult to work with, making accurate tone reproduction hard to achieve. Contact-printed direct duplicate negatives are laterally reversed, therefore the image can mistakenly be printed backwards if the photographer is not aware of the nature of the material.
If the original negatives are disposed of, the duplicate negatives become the masters. This is a major disadvantage since whenever an image is needed the master is used for printing, exposing it to the likelihood of eventual damage.
Interpositive Duplicate Negatives — Contact Duplication
The original negative is contact-printed onto film to produce an interpositive (a positive image on film). The interpositive is then contact-printed onto film to produce the duplicate negative. This process provides the most accurate tone reproductions possible. Problems in original negatives can often be corrected by using selected films and filters to reduce staining during the production of the interpositive. The disadvantages of this system are the higher production costs, the complexity of the procedure, and the added storage space required for the multiple duplicates. However, this method results in two duplicates for relatively little additional cost; the interpositive becomes the master and the duplicate negative becomes the use copy.
Interpositive Duplicate Negatives — Reduced Format, Long Roll Systems
Original negatives are copied onto 5-inch/105mm, 70mm, or 35mm roll film using a camera to produce interpositives (a positive image on film). The interpositive is then contact-printed onto film to produce the duplicate negatives. This system provides accurate tone reproduction. Also, problems in original negatives can often be corrected with the use of selected films and filters to reduce staining during the production of the interpositive. These systems provide easy access to collections. They have high production capabilities and lower production costs, and they require less storage space. However, with reduced-size duplicates there is usually some loss of image detail, proportional to the amount of reduction. As with contact interpositive duplicate negatives, this system results in two copies; the interpositive becomes the master and the duplicate negative the use copy.
Digital Imaging Storage Systems
With these systems images are stored on digital optical disks, which can be read in players that use a laser. Disk players can be interfaced with computers to allow easy cross-referencing between images and information. These systems are great access tools, but are not archival. High-resolution image files provide good quality reproductions but are impractical. They are expensive, they require more space than photographic film, and, because of their large files, they take time to access. Screen-resolution image files or files of lower quality are less expensive and do not have the storage and access time problems; however, their resolution is only fair.
The technology for optical disks is still in flux. Professionals estimate that innovations in disks and computer hardware and the design of new software to use them necessitate replacement of systems every three to five years. Therefore institutional budgets must include funds to continually upgrade the systems with new software and hardware. Also, no standards have yet been developed to insure the translation of information from one generation to another.
Written by Gary Albright