Re: Argyrotype and Bergger COT 320

Hi Loris,
So glad you are doing argyrotype with your methodical testing way; I learn
from you.

I do not get any bleeding with argyrotype but I did mix up my formula to
include Tween in it, as Ware recommends. I added 10 drops of 50% Tween 20
per 100 ml (I wish Tween wasn't called Tween 20 because i assume it is 20%
when it is not). However, I will NEVER do that again--mix the Tween into
the bottle of formula--because certain papers need more or less Tween than
others. But I sure do not have any coating problems with argyrotype that I
have noticed since I did it that way.

Also, I found it weak on Platine, and whether that was because of lack of
humidity (it runs about 15-20% here in the winter) or that Platine is
unsuitable for argyrotype as my notes have suggested, I have not gone back
to prove. It looked a weaker, grayish brown color instead of the deep rich
bittersweet that it should be.

I never found argyrotype to lack in the dmax department in general (aside
from this Platine thing), which I do with VDB at times. I never double
coat.

I gave the students their midterm a couple weeks ago. It was odd for me to
have test questions on Mark Nelson and Mike Ware and actually be able to
talk/email to the people I am writing tests about :) I have to give them
kudos because they have got the digineg part loud and clear. But for some
unknown reason they didn't test as well on the "gum myths" section.
Hmmmm...something's wrong with this picture.
Chris

> I had time to test Bergger COT 320 only. See the result here:
>
> http://www.loris.medici.name/Argyrotype_on_COT320.jpg
>
> Dmax is very nice - I think Argyrotype is a remedy for my "double
> coating illness" with Vandyke. Kudos Dr. Ware.
>
> I noticed two problems with Argyrotype + COT 320 combo:
>
> 1) Bleeding (albeit in a much lesser extent than Vandyke in many papers
> - but it's there).
>
> I drained the washed (about 3 minutes, 3 water changes) print for before
> fixing for 1 min. and the paper stained in the direction of draining
> (see the left / lower-left edge of the image).
>
> 2) Staining in the image area under dense parts of negative
>
> I think most of the staining is due to bleeding. Will also try to use
> less sensitizer. FWIW, I will also try to process in citric acid.
>
> I used a brush to coat Argyrotype emulsion to COT 320. Absorption is
> poor, the paper doesn't absorb Argyrotype as easily as it does with
> Ziatype (or New Cyanotype) emulsion. I guess addition of something like
> Tween can help in curing both problems 1 and 2. COT 320 is not an easy
> to coat paper anyway (very very smooth)... Probably amnt. of sensitizer
> also is critical. It took long time to coat paper, I made many passes.
> Will try a glass rod + using less sensitizer next time.
>
> When Argyrotype doesn't work on a specific paper, what problems you get?
> According to what you see, do you think COT 320 can be made to work with
> Argyrotype?
>
> TIA,
> Loris.
>
Received on Tue Apr 4 07:59:52 2006