[alt-photo] Re: no shrink, no size tricolor gums

[Paul Viapiano]

Don't forget that it depends on your negative as well...if your neg is too 
thin it'll take a long time to clear.

What's your gum/pigment ratio? My general baseline is: 1 gram pigment / 9 ml 
gum PLUS an equal amount of potasssium dichromate; so if I use 4ml of that 
gum/pigment mixture I use 4ml pot di, a 1:1 ratio.

Using a silver neg of approx 1.2 DR roughly, and a 2 min full sun California 
desert exposure, the above ratios should give you a decent image on unsized 
watercolor paper, ie Fabriano that clears in 30 minutes of still 
development.

Of course, there are so many variables in most of these processes that it's 
nearly impossible to duplicate others' experiences, but that being said I'm 
pretty sure I can duplicate my process pretty much anywhere, give or take a 
NuArc machine for the sun sometimes;-)

I've gravitated towards digital negatives with much higher DRs than is 
normally recommended for gum, with great repeatable results, but it took me 
a year to get there. The negs are made for palladium exposures of approx 4 
min in full sun. These are used for one coats and for tricolor work. I've 
also used waxed paper negs with great success as well, but of course every 
change will make you jump through hoops until you find the sweet spot again. 
Note-taking is a must and keeping everything you print for reference will do 
wonders for actually learning the process inside and out.

I found that when I started abandoning the dogma concerning gum and 
listening to my own results speaking to me, I got what I was looking for, or 
at least a repeatable baseline to springboard off from and enjoy the 
incredibly personal process that gum can be. You'll find that almost 
everyone works so differently, but all produce beautiful work...

Paul


----- Original Message ----- 
From: "Charles Ryberg" <cryberg at comcast.net>
To: "'The alternative photographic processes mailing list'" 
<alt-photo-process-list at lists.altphotolist.org>
Sent: Tuesday, September 14, 2010 9:33 AM
Subject: [alt-photo] Re: no shrink, no size tricolor gums


> Loris--I would love to get my wash times down to 30 minutes, but I don't 
> know how.  I determine exposure with 21 step strips--find the exposure 
> which merges 1 and 2--multiply by .7 and get, depending on color, between 
> 2 and 5 minutes.  The trouble is, I don't get paper white for an hour, 
> maybe and hour and a half.
>
> So, am I using too much or too little dichromate?  too much or too little 
> pigment?
>
> I'm doing some tests this week, but any advice is welcome.
>
> Charles Portland Oregon
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