[Alt-photo] Re: GUM: problematic yellow?

[Luciano Teghillo]

Hi Diana,

Yes the paper works great. I cannot thank you enough for the suggestion!
I will need to get my color wheel out and see if I can find another yellow
in the Maimeri pigments that works with my combination of colors (which I
still need to prove when layered together) or maybe try a different gum.

I hope I can solve this one quickly, test my inkjet negatives and get on
with some prints...step wedges are boring :-)

Luciano




-----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
Diana Bloomfield
Sent: Wednesday, February 05, 2014 6:55 PM
To: alt-photo-process-list at lists.altphotolist.org
Subject: [Alt-photo] Re: GUM: problematic yellow?

Hi Luciano,

I'm so glad you manage to get some of the Fabriano and work with it, and
that you like it.  It is pretty amazing paper, isn't it?  

That's interesting about the yellow.  I know people always say they often
have trouble with the blue pigment, but I never hear anyone talk about
problems with yellow.  But I never had a problem with blue-- not sure why--
but I always always seemed to have issues with yellow, until someone (on
this list, I think) suggested Quinacridone Gold for yellow.  I can't
remember now which yellows I used that gave me so much staining-- they all
seemed to as I remember-- but ever since I switched over to Quinacridone
Gold (Daniel Smith or M. Graham), I haven't had a problem.
I also don't make stock solutions, so can't help you there.  But my
(unscientific) thought is that it's the pigment itself.  If you can find the
Quinacridone Gold somewhere, it would work for you.  I also like it as a
yellow layer-- as it's not so much an in-your-face-yellow-- as it is a rich
gold.

Diana




On Feb 5, 2014, at 12:27 PM, Luciano Teghillo wrote:

> After Diana suggestion (thanks again) I was able to source some 
> Fabriano Artistico soft-press and I was able to print some exposure 
> tests. The paper is great! I am not getting any stains, and finally I 
> am printing something, even if they are only step wedges without having to
pre-shrink, size, etc.
> etc.... The final test will come as soon as I can print more layers....
> 
> So far no problem with blue
> (http://www.lucianoteghillo.com/images/scan-blue.jpg) and red
> (http://www.lucianoteghillo.com/images/scan-magenta.jpg) but yellow 
> it's not printing correctly, at least that's my impression.
> 
> After the first test
> (http://www.lucianoteghillo.com/images/scan-yellow1.jpg) with the 
> usual exposure times used for blue and magenta (from 1 minute to 3.30 
> minutes in 30 seconds intervals), it looked like I was not reaching 
> maximum "black" but also the steps didn't look as defined as with the 
> other colors. So I decided to print one more test with exposures of 
> 16, 32 and 48 minutes 
> (http://www.lucianoteghillo.com/images/scan-yellow2.jpg). I think this
second test is event worst than the first.
> 
> Now everything is the same: same gum, same potassium dichromate, same 
> process. I mix a stock solution with 15ml tube and 45ml of gum, which 
> I then further dilute as needed. In the case of yellow, I mix 1ml of 
> stock solution with 1ml of gum and 2ml of 12% potassium dichromate.
> 
> The watercolor used for yellow is Maimeri Blue, Primary Yellow, PY97 
> (Arylide yellow, also known as Monoazo yellow).
> 
> This might be important or not, but I noticed some separation between 
> gum and pigment in the stock solution bottle. If I let the bottle rest 
> for a day, I can see a ring the color of gum 1/4" thick on top, 
> something I did not notice with the other colors.
> 
> Do you have any advice? I do not have other yellow tubes from other 
> pigments/brands but I could look for it. It just seems strange that I 
> cannot print this color!!!
> 
> Thanks,
> Luciano
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