Some slides in my archive have deteriorated to the point of being totally unrecognisable (see image below)
However, most are in reasonable conditions and unlike the slide above, many are restorable.
The slides that have been stored in non-archival plastic slide-sleeves have presented the biggest problems. Over time, the plastic had disintegrated which leaves a fine spray over the film. When this ‘spray’ hardens the slide is irreparably damaged (as above) and it is impossible to physically or digitally clean them. However, when the ‘spray’ is still moist, it is possible to save the image.
Sometimes, it is easy to remove the ‘spray’ with a ‘Magic Lens Cleaning Cloth’. However, even this process it has to be conducted with great care as you can easily scratch the slide surface in the process. I found that the best practice was to take the slide from the mount and to place it on a ‘lens cleaning cloth’ and then carefully apply pressure to the slide with a second ‘lens cleaning cloth’. This process helps to avoid any further scratching.
There were many instances when this was not sufficient preparation for the digital cleaning. In these cases a series of experiments took place – some worked, some didn’t and others required a combination of a number of techniques. Some slides were destroyed in the process.
Cleaning with soap and water (the easy option)
Soak the slide for at least half an hour in cold water. Take it out of the water and then apply domestic hand soap that you can buy from the supermarket to your fingers and rub across the surface. Rub vigorously between your fingers and then wash under running water until the surface is clear of the soap. Then place the slide into cold water again for at least half an hour.
Cleaning with chemicals (the difficult challenge)
Soak the slide in a solution of 1:200 of a mixture of methylated spirits and water (1:methylated spirits/ 200:water) for no more than 3 minutes. Remove from solution and wash in cold running water. Then place in a 1:200 mixture of Infotol and water (1: Infotol/ 200 water). Wash under running cold water then place in a container of cold water for at least 20 minutes.
NOTE: This is risky business as it is possible to remove or damage the emulsion side of the slide. However, when there is no alternative, it is worth the risk. Also, a photographer once told me that cloudy ammonia in a very, very diluted form is also good. Let’s say 1:100. The after soaking the slide in this solution, you wash it in a photographic wetting agent at the recommend dilution ratio. He says that you can take slide out if it's mount to do this or leave in its a laborious process to take every slide out I left them in their mounts Good luck with this I did about 100
Drying after washing
As I work from my home and not in a sterile environment, the drying process is exposed to dust and particles. The way that I dealt with this problem was to install a string of fishing line in the laundry area of the house and to attach the slide to the fishing line with a very small ‘pullback clip’ (stationery item). This allowed me to attach the slide at a corner of the unit and to minimise the possibility of scratching the slide. I then laid a cover of gladwrap over the slides, which was designed to minimise contact with dust particles.