U of S | Mailing List Archive | alt-photo-process-l | Re: Bleach-development with gum

Re: Bleach-development with gum

Wow, that's great Marek; thanks for putting these up. You can especially see it in the test strips, thanks for including those.

I'm not inclined to credit the idea that my mottling was due to weak pigmentation, because the pigment in both of my examples was way more than I'd usually use for a one-coat of lamp black; I was in fact sort of tentatively attributing the mottling to a too-heavy gum layer necessitated by the too-heavy pigment load. There's so much pigment in the mix that it simply can't be brushed on thin; the only way to brush it on thin would be to add liquid to the mix, which I think would rather defeat the purpose. But I'll experiment with lowering the pigment load and seeing if that makes it better or worse. It doesn't make sense to me to try to put more pigment in, above the heaviest mix I already tried. But I wish we had a way of comparing actual amounts, even though they're not very comparable if we're using different pigments or brands. And yes (I guess I forgot to say this earlier) I'd be glad for your notes.

At any rate, your examples have spurred me to new efforts; I'm going to increase the bleach for starters, then experiment with changing the dichromate concentration. And I'll just do Stouffer strips to start with, because I'm using up too much paper printing test prints, even on 1/8 sheets. (I just noticed in the Daniel Smith catalog that my paper, that used to be something like $65 for a 25-sheet pack, is now $92!).

Just to clarify from the earlier discussion: I didn't post the comparison print made by my usual method to demonstrate any superiority of my usual method, only as a standard to judge my failure with the bleach development by.

Yeah, I like experimenting. Or you could say I have a highly developed intellectual curiosity.

On Dec 2, 2007, at 9:01 AM, Marek Matusz wrote:

All gummists:
Here is a sample of prints made by bleach development. I also made some test strips that illustrate what I might have omitted, or was not evident. Bleach development allows for a long tonal scale of the print with a very smooth tonal gradation from light to o dark. I think this is perfectly illustrated in the test strips
On the other hand, I was doing some tricolor yesterday and I have tried my blue (indanthrone ) weakly pigmented layer (weakly pigmented by comparing to "direct carbon method") and I got the same mottled development as Katharine, even worse. Actually it was this that prompted my to coat the pigmented solution made in May this year and repeat the procedure as excatly as the notes would allow. It worked beautifully. I am not even trying to figure this out since I used the same paper, same procedure.
The two pictures in the link were made with same pigment/gum mix. Brownish print has some perylene maroon added to basic carbon black stock.

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