[Alt-photo] Gum pigment mixed in batches

Francesco Fragomeni fdfragomeni at gmail.com
Tue Jan 30 05:33:05 UTC 2018


Hey everyone! Thank you for all of the responses. I’m in the middle of some
international travel and have been super delayed in catching up and just
seeing all of this now. Really great info! Thank you!

-Francesco


On Tue, Jan 9, 2018 at 12:38 PM Christina Z. Anderson via
Alt-photo-process-list <alt-photo-process-list at lists.altphotolist.org>
wrote:

> Marek,
> You never cease to amaze me. I have NEVER thought of freezing it.
> Chris
>
> Christina Z. Anderson
> Contemporary Practices in Alternative Process Photography series <
> https://www.routledge.com/Contemporary-Practices-in-Alternative-Process-Photography/book-series/CPAPP
> >
>
>
> > On Jan 9, 2018, at 8:30 AM, Marek Matusz <marekmatusz at hotmail.com>
> wrote:
> >
> > I mix a fresh batch from gum stock and dichromate solution for a
> printing session. However I hate to discard premixed gum dichromate pigment
> mix after a day if printing if there is left over solution. I have frozen
> the mix and kept it for weeks and used it. Never noticed any ill effects.
> > Marek
> >
> > Sent from my iPhone
> >
> >> On Jan 9, 2018, at 9:18 AM, Christina Z. Anderson via
> Alt-photo-process-list <alt-photo-process-list at lists.altphotolist.org>
> wrote:
> >>
> >> Francesco,
> >>
> >> What everyone has said is good but I’ll add one thing.
> >>
> >> When I came across a mention back in the day (1800s) of a practice of
> mixing the gum/pigment/dichromate up 48 hours before use to “ripen” it, it
> got me wondering.
> >>
> >> So I took some gum and dichromate and mixed it up and left it in the
> dark for five days and then one cup put in the sun and then the dark for
> the same period of time to see both light and dark reaction (no pigment so
> it wouldn’t be influenced by color). Sure enough, it slowly darkens and the
> gum/dichromate that was left outside for a bit got dark gooey lumps in it
> and looked like molasses. The one left in the dark only got to a dark
> orange color.
> >>
> >> However, it did not, surprisingly, harden solid all the way through,
> but was a sort of syrupy liquid.
> >>
> >> Then I exposed both of those solutions on paper and they both exposed
> and hardened as expected, but the one from outside resulted in a dark lumpy
> layer.
> >>
> >> Not best practice, of course!
> >>
> >> But what it did teach me was that when I do workshops where we are gum
> printing the whole week, I mix up a batch of dichromated colors (magenta,
> blue, yellow) and we use them until they are used up. Perhaps 1/4 cup of
> each color, enough for 12 or more 8x10s. They last fine and work well for
> 24-36 hours. Maybe even 48 but I have not tested them longer because they
> are usually used up by then. And this is in regular room light. I’ve done
> this for quite a while now so it is “time tested.” And at home I’ll do the
> same with smaller batches, i.e. I do not toss the extra
> gum/pigment/dichromate until the end of the printing session.
> >>
> >> I do keep all gum and colors premixed in 250 ml plastic bottles so at
> time of use I only have to squirt the colored gum into a cup and add
> dichromate. SO much easier and no lumps of color that streak your paper.
> >>
> >> Chris
> >>
> >> Christina Z. Anderson
> >> Contemporary Practices in Alternative Process Photography series <
> https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.routledge.com%2FContemporary-Practices-in-Alternative-Process-Photography%2Fbook-series%2FCPAPP&data=02%7C01%7C%7Ca91f27896e774f3db44908d5577436b7%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636511078999737488&sdata=Xd%2B4m8wSppfa4Z9CbO2A4K0Witxo5bNt2AxsFpjUWxs%3D&reserved=0
> >
> >>
> >>
> >>> On Jan 8, 2018, at 9:44 PM, Francesco Fragomeni via
> Alt-photo-process-list <alt-photo-process-list at lists.altphotolist.org>
> wrote:
> >>>
> >>> Hi all,
> >>>
> >>> Quick question. I'm sure this has been asked but I can't find it. Can
> gum
> >>> bichromate pigment be premixed in larger batches rather than being
> mixed at
> >>> coating time? I'd like to mix stock pigment solutions and keep them
> stored
> >>> in glass bottles that I can reach for across printing sessions (rather
> than
> >>> mixing fresh for each print). Is there any reason not to do this? I
> think
> >>> I've heard of people doing this but wanted to double check. Thanks!
> >>>
> >>> -Francesco
> >>> _______________________________________________
> >>> Alt-photo-process-list | altphotolist.org
> >>
> >> _______________________________________________
> >> Alt-photo-process-list | altphotolist.org
>
> _______________________________________________
> Alt-photo-process-list | altphotolist.org
>


More information about the Alt-photo-process-list mailing list