Re: gum printing, technical and looong

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Ender100@aol.com
Date: 02/28/03-05:02:39 PM Z


This idea comes from Sam Wang, not from me. It's another view on the
staining issue and it is very simple and makes a lot of sense to me—Thanks
SAM!

One issue of staining with gum, as I have read—correct me if I am wrong,
don't correct me if I am Wang... anyway, as you add more dichromate solution,
you add more water, which in turn dilutes the gum... the thicker gum is
"supposed" to keep the pigment in emulsion and protect the paper from
staining.... however, if you use powdered dichromate instead of the usual
saturated solution, you are not diluting the gum.....

Mark Nelson
(Lurking & Listening Pays Off)

In a message dated 2/28/03 11:28:42 AM, zphoto@montana.net writes:

<< Second, as far as pigment stain, is it possible (I'm still on this

acid/alkaline wavelength so bear with me) that the more dichromate added to

the sensitizer mixture, the more acid the mixture, and the more the paper

stains because the acid "mordants" the color to the paper, as in dye

mordanting or etching in mordancage? Like when you were a kid and dyed

easter eggs and you used vinegar to "set" the dye? I came up with this idea

as I was cyanotyping in my bathtub, and decided to try some straight

vinegar, and it nicely fixed blue cyano solution ALL over my porcelain tub. >>


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