Re: Gum - what am I doing wrong?

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BobWicks@aol.com
Date: 04/06/02-08:52:11 AM Z


In a message dated 4/6/02 8:23:31 AM Eastern Standard Time, jsmigiel@KVCC.EDU
writes:

> : nashcom@btinternet.com, alt-photo-process-l@sask.usask.ca
>

Hi David and Joe:
I read your correspondence dated 4/6 and would like to make a comment that
might be of help to you. First, the exposure of a gum print from my
experience, using a photo flood lamp at 19 inches is about 60 to 90 seconds.
Over exposure will result in solarization and if the exposure is long enough
it will produce a complete reversal of the image. Using the sun is OK, but
remember that the exposure becomes very subjective and can be subject to
inconsistent results. I store my sensitizer in an amber bottle and have used
it successfully even after it was 10 years old. I always mix the emulsion
and the coloring agent just prior to application for best results. For the
washout you need to be pretty certain that your tape water is not hard water.
 If you are in doubt, just use distilled water. Water that contains high
alkalinity will cause a breakdown of amino acid chains which creates the
emulsion from dissolving in the washout.

I hope you find this helpful. Good luck.

Bob Wicks
Professor Emeritus Art/Photography
Harrisburg Area Community College


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