But that is only the beginning most modern processing machinery does a more than adequate job of hypo removal. Proper processing is still important, everyone agrees on that. What scientific evidence exists, and what do Kodak and Fuji think about all this? Now you are saying that corrosion of silver is the key. Question: We were always told that proper processing was the main issue in archival permanence.
No, SilverLock-treated microfilm still should be stored in the recommended temperature and relative humidity (RH) conditions, because the gelatin emulsion and film base are subject to deterioration.ħ. Question: Does treating SilverLock mean we no longer need to have environmental controls? The longer we expect the film to last, the more time there is for slow processes or corrosion to occur.Ħ. In addition, HVAC equipment can fail, or not be maintained for lack of funds. A simple analogy: it is better to vaccinate against disease than rely on avoiding exposure to germs. In most actual occurrences of red spots or fading, the specific sources of contaminants cannot be pinpointed. For example, many building materials - paints, plastics, adhesives, concrete sealants - can give off peroxides. Question: If we provide a vault that has proper controls, use archivally safe boxes, and watch our air quality, isn’t that good enough? Why do this treatment then?īecause there are so many potential sources of contaminants that cannot be foreseen and that may be very close to the film.
While there is really no substitute for a healthy storage environment, SilverLock can be regarded as a cheap insurance policy against the many hard-to-control environmental contaminants that can damage microfilm over the long haul of archival storage.ĥ. It makes film chemically resistant to damaging atmospheric agents, without altering important film characteristics. SilverLock creates a pollution barrier, too - right on the film itself. Archives have installed expensive environmental monitoring and maintenance systems in their vaults to protect their stored film from atmospheric pollutants that degrade silver. Most micrographics people are aware of the deterioration problems of microfilm in long-term storage, and some go to extraordinary lengths to prevent them. High humidity, high temperature, and oxidizing and reducing gases all work together to take their toll on silver gelatin emulsion imaging media. The typical photographic storage environment can present stresses and atmospheric pollutants that may damage or destroy silver images. But, presupposing an ideal world can lead to trouble in the real one. Microfilm, properly processed and stored under ideal conditions, is indeed considered to be archival and will retain information indefinitely. Question: Why should I treat microfilms at all? Aren’t they archival already? Backstage will apply polysulfide treatment to film produced in our studios or to film produced by other organizations.Ĥ. Although the formula is freely available, controlled testing and specialized equipment are required to formulate the raw materials of the polysulfide solution to the IPI formula.Ĭurrently, Backstage Library Works is the only organization producing SilverLock that is tested and certified by IPI. Some organizations increased inventory of IPI’s SilverLock, however, at some point these supplies will be exhausted. In 1997, IPI discontinued the production of SilverLock. The specific purpose behind the design of IPI SilverLock was to ensure the stability of preservation microfilm.ģ. Work was supported by grants from Office of Preservation, National Endowment for the Humanities (NEH) the National Historical Publications and Records Commission (NHPRC) and the New York State Library Preservation Grant Program as part of a general effort to preserve the informational content of the nation’s brittle books. The formula for SilverLock was developed by the Image Permanence Institute (IPI) as a result of five years of federally funded research.
SilverLock completely prevents red spots. The silver in a film emulsion can react in somewhat the same way, except that the deterioration typically appears in the form of spots (sometimes referred to as red spots). Metallic silver is very susceptible to oxidation - a fact you can appreciate if you have a silver table service that must periodically by cleaned of tarnish. It does this by converting most of the metallic silver that makes up the image to silver sulfide. SilverLock is a protective chemical bath that makes silver film resistant to the effects of atmospheric pollutants. Question: What is SilverLock? Will it prevent red spots? This document was originally created by the Image Permanence Institute (IPI), modified by Backstage preservation services, and approved by IPI.ġ.
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