A nasty little infection? - Fungus on Kodachrome and other slide film

[pdeeh]

A dozen or so boxes of mounted 35mm colour slides has recently come into my possession - so, perhaps 300-400 individual slides.
These are my family's holiday and special occasion snaps, some on Kodachrome, some on a variety of "Boots", Ferrania/3M and other brands.
They date between the mid-1960s and perhaps late 1970s, and had (unfortunately) been stored for the past few years in a polyethylene bag in an outdoor concrete shed.

My intention was to scan them and distribute electronic versions to the remaining members of the family.

Opening one or two of the boxes, some seem to be fine, whilst others seem to have suffered deterioration.

An example is linked below. If I saw this on a lens, I'd assume it was fungus.

I am rather disinclined to put these through my scanner as I don't particularly want to distribute spores about the place (assuming this is fungus), and especially don't want spores transferred to any of my current B&W negatives which might also go through the same scanner.

Am I worrying unnecessarily?
Is there an easy way to cleanse/disinfect the damaged slides? (I mean by me - they are almost certainly not worth having professionally restored, even if that is the only way forward)

thanks for any advice

[bsdunek]

If the fungus has eaten into the emulsion, damage has occured and cannot be reversed. I have used PEC-12 cleaner and PEC Wipes to clean slides, and it does take the fungus off. It will at least improve things, and is worth a try.

[Jim Noel]

If it is a fungus, use Listerine, the original not the highly flavored. That is what the Leica Users Group used to recommend for lenses with fungus.

[flash26c]

A lot of my Vietnam slides have a fungus. I always thought it was non-reversable; guess it's worth a try to salvage them.

[Bob-D659]

Original Listerine is partly/mostly ethanol, don't use it and have a breathalyzer test right away. So any alcohol cleaner will likely kill the fungus, it just won't repair any damage.

[pdeeh]

I'll probably get out the isopropyl alcohol and cotton buds, as I have them to hand, and PEC12 is a useful suggestion.

I'm still interested to know whether these slides are a "danger" to my recent negative materials which might share a scanner?

(I realise that good storage is the key, as the air is laden with spores anyway so all material already has the potential to grow visible fungus, but better safe than sorry I suppose)

EDIT

Aha! I just found an APUG post by no less than PE, who notes that the remaining silver in B&W negatives acts as an effective deterrent to fungal growth; in the same thread he and others note the use of formalin to kill fungus, and that's pretty easily available (though nasty stuff)..

So I reckon I could clean off the slides as best as I can with either IPA or formalin, and then not worry too much about "infection"

[Steve Roberts]

Fungus on the emulsion side will have eaten in and caused permanent damage. In my experience you can easily make things worse by trying to remove it. I normally clean the fungus from the non-emulsion side then dunk the transparency in carbon tetrachloride (for a minute at most) and allow to dry. As has been said, that does nothing to repair damage but should kill the fungus. This was the advice I was given many years ago by a friend at our local film archive. Apparently carbon tet can be nasty stuff, so leave a window open.
Cheers,
Steve

[MartinP]

If I remember correctly, carbon tet can dissolve many common plastics, so if you use it do so in a glass container (a.k.a. a jam jar) not your best developing tank or reel . . !

[pdeeh]

thanks for all the extra info.

I thought carbon tetrachloride was banned from sale or use in the UK long ago? Can you even still buy it? Or am I thinking of trichlorethylene?

These aren't valuable enough to go to the trouble of removing them from the mounts and so on, for proper conservation. I'm happy to give 'em a careful wipe down with whatever's handiest so they're scannable and make the best of whatever images are still there. There are (sadly) no further generations to hand them on to ...

[dnjl]

Just out of curiosity, would microwaving the slides kill the fungus while leaving the film intact (and dry)?