U of S | Mailing List Archive | alt-photo-process-l | Re: gum question

Re: gum question

BTW, a tip (this was very useful to me) can be:

If you (absolutely) want nicely calibrated negatives suitable for gum,
just calibrate for cyanotype on your usual paper (the one that you use for
pt/pd or argyrotype - if you already don't do cyanotypes, that is) and use
those negatives for gum.

You'll just have to adjust your coating solution / exposure and
development according to the negative. Sounds complicated but believe me
it's much easier that way! (Pretty effective and successful too.)

Just pay attention to not exceed 14-15 steps in the 31-step tablet with
your cyanotype sensitizer; over that (log 1.5 DR), it's a little too
strong to work comfortably with gum.

I currently use 2A+1B trad. cyanotype, and it gives me exactly 15 steps
(including dmax and paper white). Those cyanotype negatives print gum very

I always had better results (due my particular working style and/or
materials?) with weak sensitizers; I use only two dichromate strenghts 5%
and 2%. (AD, 1+1 gum/pigment+dichromate.) I also have 10% on hands for
unusual situations though.


28 Mayıs 2009, Perşembe, 12:50 am tarihinde, Paul Viapiano yazmış:
> Loris...
> Yes, like a painter. I'm so glad you said that...
> I'm experimenting with one-coats and gum-overs...learning much on every
> exposure.
> Taking notes, as I always do, even for silver prints...
> When I have something to show you, I'll post a link.
> Thanks for the reply...much appreciated.
> Paul
> ----- Original Message -----
> From: "Loris Medici" <mail@loris.medici.name>
> To: <alt-photo-process-l@usask.ca>
> Sent: Wednesday, May 27, 2009 2:04 PM
> Subject: Re: gum question
>> For stock gum/pigment solutions I do as you describe, in case of adding
>> pigment from tubes I use 1 part dichromate to 1 part of gum + the
>> pigment.
>> (I tend to use strong pigments in small amounts, therefore I
>> assume/accept
>> both working styles as being equivalent.) The pigment amnt, exposure
>> time,
>> dichromate strength, development time/method all will change relative to
>> each other and most importantly to your goal for that particular layer.
>> It's not rocket science at all; just try to establish "the feel" by
>> experimenting (changing only one variable at a time) and good note
>> taking.
>> Don't try to work by numbers only, it's counterproductive and boring
>> (you'll understand what I mean if you try to calibrate gum). Try to work
>> more like a painter, you'll see that it starts to  become (or, better,
>> the
>> general direction of your working style will be) second nature after
>> some(!) experience. ;) (Not that I'm implying I have lots of
>> experience...)
>> Regards,
>> Loris.
>> 27 Mayıs 2009, Çarşamba, 11:38 pm tarihinde, Paul Viapiano yazmış:
>>> If I premix gum and pigment together, would I still use equal amounts
>>> of
>>> that mixture and pot dich to make a 1:1 solution?
>>> Do I need to account for the pigment being already mixed in there?
>>> Thanks...
>>> Paul