Technique for cleaning slides with isopropyl alcohol

I have recently noticed that some of my slides have small spots of

what looks like mould. Having done some research on what to do

about it, I have purchased some isolpropyl alcohol.

Can someone advise me on the best technique for using it? I have

experimented with a few old slides, and I find that it doesn't

evaporate readily, and tends to leave streaks on the slide.

Presumably I need to apply a drop to the mould and then wipe it with

some sort of cloth to remove the mould before it dries? How do you

avoid scratching the slide?

<p>Have a look at Kodak publication F-30, <title>Preservation of Photographs</title>. Unfortunately, not available online, and apparently out of print. (Hmm, Pacific Rim Camera has a copy for sale.)</p>

<p>Fungus is a nasty problem. First rule is segregation -- don't leave them near anything uninfected.</p>

<p>The book notes that when fungus starts eating film, it makes the gelatin base water soluble. This makes life tricky.</p>

<p>As for the streaking, you probably need purer Isopropyl alcohol. See your druggist, he probably has very pure stuff behind the counter to sell. Or go to a chemical supply house for 2-isopropanol.</p>

<p> I don't think that it can kill the fungus. Probalem is that things that can kill the fungus can also damage the color dyes, or kill you. (Kodak used to publish some formulas for film preservatives for humid locales, and they were mighty toxic.) <a href="http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=000GoB">See this old thread</a>.</p>

Formaldehyde will kill fungus as will benzoic acid.

Unfortunately, they are used from a water solution, so if the fungus action is far enough along, goodbye emulsion.

Benzoic acid can leave a residue, so it is usually used on film.

The best thing is to clean them with C41 stabilizer and then with a commercial film cleaner, provided that the gel has not been weakened too much.

Best of luck.

Ron Mowrey

Ron,

Isn't C41 stabilizer concentrate mostly water?

See Kodak Tech Pub at:

http://www.kodak.com/cluster/global/en/consumer/products/techInfo/ae22/ae22.shtml

Or the PDF link below...

Dan and others;

C41 stabilizer is mostly water, that is why I suggested caution in its use. It can dissolve a badly infected negative or slide due to the action of fungus. Incidentally, IPA (iso propyl alcohol has a percentage of water in it as do most all alcohols so you have to be careful. Sometimes IPA with a chlorinated hydrocarbon (some commercial film cleaners) are better to work with as they minimze water problems in the solution)

On the other hand, please note that formaldehyde is a very powerful fungicide and also a gelatin hardener.

So, in the early stages of infection, it can not only kill the fungus, but reverse some of the softening damage. The problem is telling how far the infection has progressed, and that takes experience and trial and error experiments.

I suggest using the concentrate at normal dilution or perhaps 2x strength. It will take some experimentation to determine this as well. You also have to work in a well ventilated area to preserve your lungs and eyes from fumes.

I have heard of people fuming the film in formaldehyde fumes by hanging the film in a jar with formalin 35% solution in the bottom of the jar. I have never done that, but it is a method used to preserve specimens in biology. Someone might want to look into it here. It was discussed years ago in photographic restoration circles. I'm surprised no one has brought it up here. It is a nasty method to use for the average person, and concentrated formalin is hard to get. Sometimes you have to make it from paraformaldehyde.

As the EK publication says, this is a very tough problem to deal with. I too have lost slides this way, but so far, no negatives for some reason.

I wish you the best of luck recovering your materials.

Ron Mowrey