How to clean gunk off of transparencies?

[larry_huppert1]

O.K. Inspite of best efforts, disasters can happen...

 

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A problem with my compressed gas (nitrogen) setup which I use to dust off film prior to scanning left some small gobs of gunk on one of my transparencies. It appears to be an oily deposit. What is the best way to remove this gunk off of the transparencies?

 

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I've since found the source of the problem, and corrected it. It happened to be a bad regulator which my gas supplier gave me.

[dmin-99]

PEC-12

[pete_andrews]

Sounds as if you need a hepafilter in your air line Larry.

[larry_huppert1]

Pete,

 

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The problem was fixed without a filter. My gas supplier gave me

a regulator when I got this nitrogen tank. Last week I went back

to the gas dealer and we found the problem by switching out all

the components one by one. The old regulator somehow ended

up with gunk which mixed with the gas. Getting a new regulator

solved the problem. Just a proof point in the saying that you get

what you pay for. Now it works great, and it's wonderful having a

huge dust-off can without the noise of a compressor.

[john_henderson1]

I find it interesting that Larry uses a cylinder of nitrogen as a

dusting device. I've thought of using my SCUBA cylinders, but never

saw any kind of hose with a regulator and a blower on it that fits the

standard non-DIN SCUBA fitting. It seems to me that the air would be

much cheaper than nitrogen (assuming you have a place to pump it), and

you wouldn't have the asphixiation scare.

[larry_huppert1]

I got the idea of nitrogen from the archieves which are part of this

site. After the initial outlay for a tank + regulator (~$130), getting

the tank refilled is *MUCH* less expensive than those Dust-Off

cans which seem to have about a dozen good shots in them

before the air pressure reduces to the point where the can isn't

useful. You also don't run the risk of having that white ick (the

propellant?) cover your stuff. I believe my tank is a 60 cubic ft

tank, and it will cost less than $15 to refill. From what others

have said, Nitrogen is one of the least expensive industrial

gases, and is suppose to be very dry and clean. I wasn't aware

that compressed Nitrogen was a significant health or safety risk.

[dmin-99]

Larry if that tank leaks in a closed room while you're around they

may have to carry you away in a black bag. Normal air contains 21.5%

oxygen - dilute that much below 18% with nitrogen and you might take

a "dirt nap". 60 c.f. isn't much - but it can be enough.

[struan_gray]

While is is possible for a 60 cu. ft. tank to reduce the oxygen

concentration in a small sealed room, the chances of it doing to

without you noticing are pretty remote - it will have to leak fast

enough to be heard. If your darkroom is sufficently ventilated to

safely use processing chemicals it's almost certainly a non-issue.

 

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The real problems with pressurised cylinders are that the neck can

break off if they fall over or are dropped. They can explode in a

fire: the local firemen tell me that of all the hazards in our labs,

it's the gas bottles they fear the most. Transport carefully, chain

in place for use, and evacuate to safety in any fire which gives you

the option.

 

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I don't have a lot of experience of removing stubborn stains from

transparencies, but PEC-12 has always worked when simple re-washing

failed.