11/13/2023 0 Comments Kimble silver gelatin printSince photographic prints are usually kept in the dark for long-term storage ( i.e. For some fascinating discussions on storage conditions for photographs, see Johnsen ( 1994), Mecklenburg et al. In addition, studies have been published on the modifications and possible improvements of these guidelines. They are reviewed by the corresponding committees about every 5 years. While these are useful guidelines, they are not etched in stone. In all of the CCI Notes on the preservation of photographic images, the suggested storage conditions are those recommended by the International Organization for Standardization. Cold-storage conditions, even below 0☌, are beneficial to the longevity of photographic prints. Avoid daily fluctuations of more than 4☌. Temperature may range from 15☌ to 25☌, but must never exceed 30☌. RH should never exceed 60%, and recent research indicates that 30–35% RH is optimum. The combination of any of these with either high RH or high temperature will lead invariably to discoloration of the image.Īccording to recommendations published by the International Organization for Standardization, RH levels between 30% and 50% are acceptable for storing photographic prints. Nevertheless, avoid such conditions because of the possible presence of aggressive chemicals such as hydrogen sulphide, peroxides, ozone, and sulphur dioxide. Properly processed prints on fibre-base paper are essentially stable when exposed to dry heat. If this has occurred, exposing the curled prints to high RH will allow them to relax and unfold. Excessively dry conditions cause prints to curl up tightly. Uniform low relative humidity (RH), a constant temperature, and the absence of reactive pollutants in the atmosphere are key requirements for long-term preservation of photographic prints. hundreds of years) than are conventional baryta papers. However, they are considered less suitable for preserving images over extended periods of time ( i.e. This enables them to be processed in a few minutes and to yield dry, flat prints. Consequently, images on printing-out papers - which include salted paper prints, albumen prints, collodiochloride papers, and certain silver gelatin prints - are more susceptible to image deterioration caused by chemical attack than are photographs on developing-out papers.Īlthough RC prints are developed-out, they possess special properties related to the plastic coating on either side of the paper base. Each is manufactured and processed differently, which results in differences in size and shape of the silver particles in the image. This group of prints may be subdivided into those printed on printing-out papers and those on developing-out papers. Like all photographic records that contain elemental silver, the image is susceptible to discoloration if exposed to aggressive chemical reagents even though it is on a stable support. They are sometimes referred to as baryta papers Endnote 1. Also, the silver particles that form the image are susceptible to an oxidation reaction that leads to discoloration of the picture.įibre-base silver prints are made on a paper base that ranks among the highest in quality and permanence. Because of the absence of a distinct image layer, they are liable to suffer from abrasion. These prints are more sensitive to agents of deterioration than are later materials. Little is known about the properties of early salted paper prints. These photographs are often collectively referred to as "silver prints." Prints in the last two groups have an image layer coated on one side of the paper support. Contemporary resin-coated prints (or RC papers) introduced in the late 1960s.Fibre-base prints, made by a handful of manufacturers from the 1860s to the present.Salted paper prints on a paper base not specifically formulated for photographic purpose they have no distinct image layer in a binding medium.Photographic prints with silver images fall into one of three categories, according to the nature of the support material: With the exception of pictures dating from the beginning of photography (the so-called salted paper prints from the late 1830s to the mid 1860s), the image silver is embedded in a thin layer that may consist of albumen, collodion, or gelatin. This Note is concerned with prints on paper or on resin-coated (RC) paper for which the image-forming substance consists of microscopic particles of silver. There are many kinds of prints, each with its own format, process, imaging materials, image tone, base material, surface gloss, and texture. ( PDF Version, 164 KB) CCI Note 16/4 is part of CCI Notes Series 16 (Care of Photographic Materials) Introductionīlack-and-white photographic prints are found in most museums, art galleries, and archives.
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