Re: Gum hardening -- top down?

From: TERRYAKING@aol.com
Date: 04/06/06-02:01:13 AM Z
Message-id: <35e.1829abc.316624c9@aol.com>

In a message dated 6/4/06 6:05:27 am, photographeur@nerdshack.com writes:

> My guess is that whatever dichromate gradient might be found will not be
> sufficient to explain the apparent lack of "top-down" hardening in gum
> printing.
>

Top down hardening occurs in gum printing just as it does in carbon printing.

The aberration of dichromate adhering to the paper results from mixtures used
being so thin, with such a preponderance of dichromate solution, that the
paper is contaminated with dichromate This is a fault in technique and
nothing to do with dichromate being 'attracted to the paper'.

If one understands the fairly simple reactions involved including the effect
of light on the dichromates and how this affects the pigmented gum, one is
unlikely to make this kind of mistake in either understandiong or technique.

Terry
Received on Thu Apr 6 02:01:31 2006

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