Cracks on kodachrome slides?

[Anon Ymous]

Hi

I collect slides and on rare occasions I notice something that looks like very fine cracks on the slide, usually near the edges. One such example can be found on the photo below. I only remember seeing them on Kodachrome slides. So, assuming that they are what they look like, what causes them? Is it just some sort of mechanical stress on the slide that causes it? Are Kodachrome slides more susceptible to this than other kinds of slides?

Thanks in advance.

 

[AgX]

Are those really cracks?

 

[Anon Ymous]

Are those really cracks?

Yes, they look like emulsion cracks when side lit and viewed from an angle. It's rather difficult to take a photo of it, but I'll try.

 

[JPD]

I hope it isn't fungus. I found this: https://arstechnica.com/civis/viewtopic.php?f=6&t=808088

All pictures I could find with mold on slides have star or snowflake like spots, but if you have a not so important slide to experiment on you could try to clean it with the method Kodak suggested in one of the posts in the link.

 

[ic-racer]

In your case it probably is no longer alive.

 

[BAC1967]

I know one way of making slides uses heat to seal the mount, maybe that affected the emulsion.

 

[runswithsizzers]

I have quite a few old slides which show the same pattern. I've always assumed the marks are fungal mycelia, which appear to be embedded in the emulsion. So far, I have not found anything that can remove it. Including alcohol, as recommended in the link, above. Notice those instructions say:
"There is no satisfactory method for complete restoration once fungus growth has etched or distorted film emulsion."

I start shooting in 1970, so some of my oldest Kodachromes may have been coated with lacquer. I did not try to determine if my slides were actually lacquered, or not, nor have I tried removing any lacquer that might be present.

 

[GRHazelton]

If you browse the Library of Congress website you will find much information on photo conservation. Perhaps the Library has some thoughts on Kodachrome.

 

[Anon Ymous]

Oh, so they're probably fungi. Too bad I don't have any isopropanol left to try cleaning some.

Once more, thank you all.

 

[koraks]

Yes, this certainly looks like fungus.