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The most important factors that affect how well a particular slide is going to keep over the years are light, humidity, and heat. The best conditions for storage are therefore dark (obvious), dry (relative humidity between 15 and 40 percent), and cool (less than 21 degrees Celsius). Cooler temperatures are slightly better, but the humidity needs to be maintained at the recommended level - too high, and fungus growth will be encouraged, and too low will cause brittleness of the emulsion.
You may find reference to "archival materials" which refer to storage containers, binders etc. made up of substances that will not damage the film. Certain woods or plastics may contain preservatives or volatile chemicals left over from their manufacture which although small in volume, could seep out over time and damage the emulsion. In the same way, reactive gasses should be avoided, bearing in mind that even gas fired central heating systems can generate an appreciable quantity of ozone which would damage films over a period of time.
Physical protection is also important, keeping the films free from dust, and any little insects that might regard your precious gelatine emulsions as lunch. Glass mounts will help protect slides, but may also help the retention of moisture.
Things inevitably will go wrong to somebody somewhere, and water damage to films is well within the bounds of possibility with burst pipes, overflowing baths etc. high on the list. Films should be separated from their enclosures, and washed for about 15 minutes in water at 18 degrees Celsius or lower. If contaminated you can swab them gently underwater with a cotton bud, but remember that the emulsion will be very soft and easily scratched. Rinse in diluted anti-smear solutions such as Kodak Photo-Flo before drying.
Properly cared for slides will last for many years, but one of the most hostile environments is the projector itself. Glass mounts can help absorb heat, but it is best to project a particular slide for no more than one minute at a time. In a hot projector in humid conditions, small amounts of moisture may condense on the relatively cold glass, which can be subsequently eliminated by storing the slides with a desiccant such as silica gel.
There is no point in having thousands of wonderful slides if you can never find the one you want- and it's important to stress the ONE. Whatever system you care to use, paper or some computer system, it is imperative that each slide receives some sort of unique reference. After this, it doesn't really matter, so design your own system, or find a commercially available one that suits you. I'm still designing mine, but will end up with some form of computerised system that contains:
For the roll:
For the slide:
At a bare minimum, you should mark each slide with its unique reference, as above. Being more sophisticated, you may decide to attach printed labels to each slide.
Ideally, it would be nice if the computer program you used to catalogue your slides could print labels for them as well. Such labelling programs do exist, although you must assess their sophistication as a cataloguing program. The Craddoc Captionwriter is one of these, specifically aimed at slide production. Avery Labelpro for Windows is a more general labelling program that can take a database provided by you and output selected portions onto 46mm x 11.1mm slide labels on A4 sheets of 84 labels (Avery stock number L7656) primarily intended for laser printers.
These labels fit nicely on standard slide mounts, and can be printed with up to six lines of information (in tiny type) on each label. You can fit either one or two labels to a single side of a slide. Unfortunately these labels are just a bit too wide for the guide rails on CS mounts, and you would have to trim the labels after they were printed.
What do you put on a label? This depends on whether it is just for your own use, or whether you send your slides out to agencies or bureaux. I would have though that the minimum that you would want to put on a label is:
(c) Copyright Mark Mumford, 1994
Rusty Parrotfish, Scarus ferrugineus
South Sinai, Ras Mohammed, 12 April 1994
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This page was last updated on 11 August 1998
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