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How do you clean gunk (grease, fingerprints, smudges, etc.) off the emulsion side of a neg?


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Very carefully lol 🤭

I use a lens cloth sightly damp with Isopropyl alcohol. A 100ml bottle was expensive to buy so I use it very sparingly and the cap needs to be tightened well after use.

Other members might know a less expensive method, but it's always best to try testing on a piece of scrap film first, whatever method you use.

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11 minutes ago, kmac said:

Very carefully lol 🤭

+ 1 to that! 

Personally, I would only use a solvent - water, alcohol, or whatever - as a last resort. Dry emulsion is a lot tougher than a wet one. 

Get some non-wet lens cleaning tissues or a new microfibre cloth, and gently draw the film through it between thumb and finger. Only applying as much pressure as needed to remove the smudge.

But if, say, a fingerprint doesn't come off with a wipe or two then wet cleaning might be necessary. As a last resort. First I would scan and digitally retouch the negative. This might be the best option with a stubborn contamination that's embedded itself in the emulsion over time. 

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If you use alcohol make sure it has minimal water content - 98% isopropyl alcohol would work - and as @kmac notes, keep the container closed!

You'll have to work on the spots with great care and as little liquid as possible - you can't just dip the film in it.

I would advice against it unless you plan to do conventional printing. It is much easier to clean up digitally.

Niels
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On 10/17/2022 at 10:06 AM, kmac said:

it's always best to try testing on a piece of scrap film first, whatever method you use.

This is KEY, test before you mess.

Edwal film cleaner is a very good product, if expensive, and hard to ship:

https://www.amazon.com/Edwal-Anti-Stat-Cleaner-Black-Bottle/dp/B00009R6YZ

https://www.bhphotovideo.com/c/product/16677-REG/Edwal_EDAFC4_Anti_Stat_Film_Cleaner_Liquid.html

However, in my personal experience a 4-ounce bottle is a lifetime supply

Edited by JDMvW
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On 10/17/2022 at 8:29 AM, rodeo_joe1 said:

+ 1 to that! 

Personally, I would only use a solvent - water, alcohol, or whatever - as a last resort. Dry emulsion is a lot tougher than a wet one. 

 

There are a few choices of solvents, with different uses.

The traditional "Film cleaner" is a hydrocarbon or chlorinated hydrocarbon.

OK, I just looked at the bottle I have, and it is tetrachloroethylene and isopropanol.

TCE is good for nonpolar things, such as grease and oils.

Alcohols are not quite as good for them, but better for other kinds of dirt, especially sticky stuff.

Many places, like grocery stores and drug stores, now sell 99% isopropanol,

next to the more traditional 70% isopropanol rubbing alcohol. 

And some things come off best with water.

-- glen

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On 10/18/2022 at 6:55 PM, glen_h said:

There are a few choices of solvents, with different uses.

The traditional "Film cleaner" is a hydrocarbon or chlorinated hydrocarbon.

OK, I just looked at the bottle I have, and it is tetrachloroethylene

I'm retired now but back when I was working, we'd us something called trichloroethane to clean relay contacts.  Wonder if that's the same stuff.

Izzy From Brooklyn
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On 10/19/2022 at 9:44 AM, MrAndMrsIzzy said:

Ehhhh!  Don't want to chance possible taking off emulsion.  Going to go with rescan and cleaning it up in PS......Izzy

Izzy, you wanted to know how to clean the emulsion side of film, now after all the replies, you are ignoring them unnecessarily.

All you have to do is take a scrap negative and practice with a clean cloth slightly damp with a proper film cleaning agent. You run the damp cloth along the film, let it dry for a tick, then inspect the film on both side by angling it in the light. The emulsion won't come off unless you're using sand paper as the cloth.

I've used lighter fluid to clean B&W and color negative film. One test I did was to pour it on a film then wipe it off, it didn't hurt the emulsion, but it cleaned it pretty good.

Cleaning is light years quicker than post processing. Just lay the film on a soft lint-free surface then lightly run the damp cloth along it, inspect, and if there's still fingerprints showing, wipe a second time. Finger prints are slightly acidic and leave a microscopic etching, so they may not remove altogether, it depends on how long they've been on the film, but you'll get the residual residue which is what can show up in the scans if it's not removed.

There's a point where cleaning must cease though. When marks are just not disappearing. When you think that you've done enough rubbing and continuing might spoil the film from the mechanical action of the rubbing. When the accumulation of dust on the cloth might start to scratch the film.

The emulsion will stand quite a bit of punishment, it's a case of not taking things too far, and make sure the cloth is a fresh cleaning cloth to start with.

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10 hours ago, kmac said:

Izzy, you wanted to know how to clean the emulsion side of film, now after all the replies, you are ignoring them unnecessarily.

All you have to do is take a scrap negative and practice with a clean cloth slightly damp with a proper film cleaning agent. You run the damp cloth along the film, let it dry for a tick, then inspect the film on both side by angling it in the light. The emulsion won't come off unless you're using sand paper as the cloth.

I've used lighter fluid to clean B&W and color negative film. One test I did was to pour it on a film then wipe it off, it didn't hurt the emulsion, but it cleaned it pretty good.

Cleaning is light years quicker than post processing. Just lay the film on a soft lint-free surface then lightly run the damp cloth along it, inspect, and if there's still fingerprints showing, wipe a second time. Finger prints are slightly acidic and leave a microscopic etching, so they may not remove altogether, it depends on how long they've been on the film, but you'll get the residual residue which is what can show up in the scans if it's not removed.

There's a point where cleaning must cease though. When marks are just not disappearing. When you think that you've done enough rubbing and continuing might spoil the film from the mechanical action of the rubbing. When the accumulation of dust on the cloth might start to scratch the film.

The emulsion will stand quite a bit of punishment, it's a case of not taking things too far, and make sure the cloth is a fresh cleaning cloth to start with.

Basically that's plan B.

The smudge is on the original scan so I assumed it's on the neg, but when I checked the neg I couldn't really tell if the smudge is there.  That being the case I figured that since I'm planning to rescan it anyway I'll wait and see what it looks like on my screen.  If the smudge is there I'll take the neg out and clean it then.  But as you point out.  I'll go easy. 

Izzy From Brooklyn
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19 hours ago, MrAndMrsIzzy said:

Basically that's plan B.

The smudge is on the original scan so I assumed it's on the neg, but when I checked the neg I couldn't really tell if the smudge is there.  That being the case I figured that since I'm planning to rescan it anyway I'll wait and see what it looks like on my screen.  If the smudge is there I'll take the neg out and clean it then.  But as you point out.  I'll go easy. 

If the smudge reappears on a rescan, chances are that you forgot to clean the scanner before the rescan.

 

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Ok!  Smudge was on the neg .  Went over it (very gently with a very clean microfiber cloth).  That pretty much took care of it.  Still a little bit left, but very little.  Rescanned as tif (original scan was jpg) and what's left of the smudge is barely visible (even at 100%).  Basically not much of a problem and easy to fix digitally.

Izzy From Brooklyn
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On 10/19/2022 at 7:30 PM, MrAndMrsIzzy said:

I'm retired now but back when I was working, we'd us something called trichloroethane to clean relay contacts.  Wonder if that's the same stuff.

This was tetrachloroethylene, so slightly different but the same idea.

More usually it is named perchloroethylene, but not on this one.

-- glen

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