[alt-photo] Re: tricolor gum problem

[Don Bryant]

Ahh the old fish eye problem.

I use a badger hair brush to eliminate the gaps from the fisheyes in the
magenta coating. 

I burnish the surface of the print lightly with the brush as though I was
polishing a leather shoe or boot. This is after the fresh coating has setup
for a minute or two.

Also note I ensure the magenta pigment is thoroughly blended with the gum
and dichromate. For that I use a dremel tool with a custom stainless steel
brush attachment which I made to quickly make a homogenous solution. But do
avoid blending to long. Extended blending will induce frothing and excessive
air bubbles.

Good luck,

Don Bryant 



-----Original Message-----
From: alt-photo-process-list-bounces at lists.altphotolist.org
[mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf Of
jusdado
Sent: Sunday, September 09, 2012 12:06 PM
To: ALTERNATIVE PHOTOGRAPHY LIST
Subject: [alt-photo] tricolor gum problem

Hi all.
After a series of prints with tricolor gum with very good results, now 
two things happen: 1. - To spread the emulsion gum, dichromate and 
magenta pigment on printing, which contains blue (cyanotype) and gum 
yellow pigment, a similar effect occurs when pour or scatter oily water 
on a surface, rather than uniformly cover, the emulsion tends to collect 
in some places and not to adhere to others. 2. - After exposure to UV 
light, the revealed, the emulsion tends to disappear, leaving the 
impression with a hideous green.
Data: equal paper and treatment, as cyanotype, like brushes, like UV 
unit and time of exposure and processing, as dichromate and 
concentration. Similarly gum prepared as above, but in this case drops 
put carbolic acid (preservative) and Scmincke watercolor pigment PR122 
same dilution 1:10,
What is happening?, Is there gum hardened by the action of carbolic acid?.
Thanks for answering and sorry for my english, translation by computer.
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