Photographic prints and negatives are best stored in individual enclosures. This reduces damage by giving the photograph or negative physical support and protection. Enclosures can be made of paper or plastic.
Suitable plastics have been discussed elsewhere in this session (see Preservation-Quality Enclosures). There are several types of individual plastic enclosures, including L-Velopes (sealed on two adjacent sides); plastic folders that can be used within paper envelopes; and plastic sleeves that are open at two opposite ends, with a self-locking fold on one of the remaining sides. There are also a number of styles of ring-binder pages for prints and negatives.
When using paper enclosures for photographic storage, conservators used to recommend that photographs be housed in low-lignin neutral paper enclosures rather than in alkaline enclosures, since it was thought that color images, cyanotypes, and albumen prints would be damaged by the alkalinity in buffered enclosures. But recent research indicates that this is not the case. Rather than choosing enclosures according their pH level, paper enclosures should be chosen based on whether they pass the Photographic Activity Test (PAT), which determines whether the enclosures contain harmful chemicals that will cause image fading or staining.
If envelopes with adhesive seams are used, the adhesive must be stable, pH-neutral, and it must not react with silver; the seams should be on the sides or the bottom of the envelope; and the emulsion of the photograph should face away from the seams.
Once they have been individually enclosed in paper or plastic, photographs must be placed in archival-quality boxes. Where possible, items of similar size should be stored together; the mixing of different sizes can cause abrasion and breakage and can increase the risk of misplacing smaller items. Horizontal storage of photographs is usually preferable to vertical storage, since it provides overall support and avoids mechanical damage such as bending or slumping. The photographs should be stored flat in drop-front boxes of archival quality housed on shelves or in metal cabinets. All enclosures within a box should be the same size, fitting the size of the box. Neutral or buffered file folders may be used to organize photographs within the box.
If necessary, vertical storage can be used. Small photographs of uniform size can be individually enclosed and placed vertically in boxes the same size as the photographs. Boxes of various sizes and types are available from conservation suppliers. For vertical storage in a filing cabinet, protected photographs should be placed in archival folders that are themselves placed in hanging file folders. Several photographs may be stored in each folder, and several folders may be placed in each hanging file. Lightly filled hanging file folders will prevent photographs from sliding down under each other in the drawer and will facilitate their handling. Alternatively, folders can be placed in archival document boxes, but the folders should not slump, and the photographs must be well supported.
Give special care to the storage of oversized photographic prints mounted on cardboard. This cardboard is often acidic, causing the mounts to become brittle with age. Embrittlement of the support can endanger the image itself if the cardboard breaks in storage or during handling. Such prints should be placed in individual folders in archival-quality boxes of appropriate size and stored flat on shelves. They require careful handling.
Negatives should be stored separately from prints. Larger negatives can be stored in individual enclosures and then boxed, while the smaller 35mm strips can be stored in plastic ring-binder storage pages. Nitrate and acetate negatives must be stored in paper envelopes that pass the PAT. MicroChamber or other proactive storage enclosures that contain scavengers to remove pollutants should also be considered for acetate and nitrate negatives.
Each type of film base should be stored separately, in a well-ventilated area, apart from other types of collections. This is particularly important for nitrate negatives. Both nitrate and acetate negatives should be monitored on a regular basis so that any deterioration can be identified early. If deterioration is discovered, isolate the deteriorating materials from those that are still in good condition. Nitrate and acetate negatives should be duplicated onto polyester film whenever possible, as this will provide a stable copy. See Session 6: Reformatting and Treatment.
Photographic Prints Storage Checklist (PDF, 232k)
Photographic Negatives Storage Checklist (PDF, 232k)