RE: pH of developer, was RE: Another Ziatype question

From: Loris Medici ^lt;[email protected]>
Date: 10/14/04-02:37:13 AM Z
Message-id: <001001c4b1c9$01208db0$ce02500a@altinyildiz.boyner>

Results that I gather from several helpful messages, to make good
Ziatypes on Whatman HP paper:

I have to

* treat the paper in 1.5% oxalic acid (for 1 min.)
* coat the paper with generous amnt. of soln. (or double coat)
* use acidic wash water (2% - 4% citric acid)

I guess my weak black problem is related to the facts: I use less than
ideal coating solution and the paper is buffered. I remember reading
somewhere that oxalic acid also weakens the size on the paper. As
Whatman HP is heavily sized, I hope oxalic will help also to make the
paper more absorbant - leading to better dmax because more image
substance will be trapped in paper fibers.

Do you think my inference is right?

Will try these precautions this evening...


> -----Original Message-----
> From: Sandy King []
> Sent: Thursday, October 14, 2004 4:22 AM
> To:
> Subject: pH of developer, was RE: Another Ziatype question
> Just wanted to again emphasize the importance of keeping the
> developer acidic in ferric oxalate based iron processes, specifically
> kallitype and palladium printing using sodium citrate developer but I
> suspect that the same would apply to ammonium citrate with both
> processes as well.
> ...
Received on Thu Oct 14 09:26:57 2004

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