Isopropyl alcohol for cleaning negatives?

Tom Stanworth · Jun 20, 2011

I had a near heart attack when I noticed a neg recently drum scanned had terrible marks all around the periphery. I then realised the dark red masking tape my printer used on the neg, well, its adhesive must have dissolved in the mounting fluid used by the scanning technician and seeped all over the neg. I just soaked it in iso-propyl alcohol and after gently rubbing with fingertips the residue came away. After a change of alcohol bath, to ensure the gunk was no longer present, I cleaned it again and it appears perfect It was a very important negative too. The worst part is they screwed up the drum scan, leaving a bald area devoid of detail and so had the neg been ruined I would not even have had a drum scan to work off!

Neanderman · Jun 20, 2011

raucousimages said:
Some brands of isopropyl alcohol have oils and other addatives to make them undrinkable.

ALL isopropyl alcohol is undrinkable!!!! Only ethyl alcohol is safe to drink.

Ed

wogster · Jun 20, 2011

Gerald C Koch said:
If any solvent containing water should get on the emulsion it will cause the emulsion to swell. Even when the emulsion dries the spot will still be visible. The gelatine becomes distorted, it has nothing to do with impurities other than water. Isopropyl alcohol does not work well with greasy deposits.

I think the key with using a water containing solvent, is to immerse the entire strip, because then the emulsion will swell and shrink in a predictable manner, just as the film does when it is processed.

This is all preventable, get some lint free soft cloth gloves intended for the purpose, only handle negatives while wearing the gloves, and keep them stored in a cool, dry place. If you don't get dirt on them in the first place, you don't need to clean them.

If they do get dirty, the best cleaning agent is distilled water with a couple of drops of wetting agent in it, you need to be very careful and remember that the emulsion will be soft when wet and can be damaged by mechanical contact.

Tom Stanworth · Jun 20, 2011

water wont get off non water soluble gunk tho. Sometimes only an organic solvent will do and as said earlier, immerse the whole strip and allow to drain naturally. I did not find drying marks an issue, but then again my isopropyl alcohol was of a very high purity i.e the sort used to mix your own photographic chemicals (and with the lowest possible amount of water).

Shawn Rahman · Jun 20, 2011

Forgive me if this has been asked and mentioned in this thread, but does the advice on this thread also hold for cleaning slides/chrome?

johnnywalker · Jun 21, 2011

Is methyl hydrate the same as methanol? I can buy it 99.9 % pure. Would there by any difference between using that and IPA (which I think I can get 99.5 % pure)?

polyglot · Jun 21, 2011

Yes, methyl hydrate is methanol. PEC-12 contains mostly methanol; I think the rest is n-butyl ester. So yes, it makes a very good film cleaner.

Cheapest way I've found to buy small quantities of methanol is from radio control shops; they use the water-free version as fuel for glow-plug engines. Just make sure you don't get the stuff that has oil pre-mixed into it for two-stroke use.

2F/2F · Jun 21, 2011

ben-s said:
I usually use a clean microfibre cloth and high purity IPA.

BTW, you can really speed up neg drying time by using a bath of 50/50 water and IPA for a couple of minutes. I believe it is an old newspaper shooter's trick. It's apparently not recommended for general use, but on the films I've used it on, I've had no ill effects.

Another "old newspaper shooter's trick" was to use a product called "Flash Dry," and then instead of hanging it, light the liquid on fire with the film still on the reel, and put it out before damage. I guess sometimes every minute counted, especially at big money, big competition events, such as awards shows and sporting events.

Now the tricks at such events are more dirty, such as buying up extra communications cables and hotel rooms even when they are not needed, just to slow down the competition's speed of getting images onto their site.

trexx · Jun 21, 2011

2F/2F said:
Another "old newspaper shooter's trick" was to use a product called "Flash Dry," and then instead of hanging it, light the liquid on fire with the film still on the reel, and put it out before damage.

Sure hope they were using 'Safety Film' Be quite a bang with a nitrate film base.

2F/2F · Jun 21, 2011

trexx said:
Sure hope they were using 'Safety Film' Be quite a bang with a nitrate film base.

Yes, of course. The people who showed me about the trick were shooting large sporting events in the '80's and '90's, mostly on color slide film.

Isopropyl alcohol for cleaning negatives?

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