Re: Another Ziatype question

From: Sandy King ^lt;[email protected]>
Date: 10/11/04-11:50:26 AM Z
Message-id: <p06020402bd9075a60517@[130.127.230.212]>

Have you checked the pH of your developer? Staining that can not be
cleared results from the formation of iron hydroxide from residual
ferrous iron, Fe(2+) in an alkaline environment. In kallitype
printing staining can take place during both development, if the
developer is alkaline, or during washing, if the tap water is too
alkaline. The iron content of the tap water, in combination with a
high pH, may also play a role. I suspect that the same goes for
Pt./Pd. printing since residual ferrous iron is a reduction
by--product.

Sandy

>I have staining problem with Ziatypes. I do the first (2 mins.) wash in
>plain tap water. Do you think I can prevent staining by washing in 4%
>citric acid in place of tap water (...like S. King suggestion for
>Kallitypes - if I remember correctly...)? Maybe the iron content of the
>tap water is inadequate?
>
>Actually this is my usual workflow for Vandykes... My AFO solution is
>fresh BTW.
>
>Thanks in advance,
>Loris.
Received on Mon Oct 11 11:48:56 2004

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