RE: glut

IME, the practice of sizing with gum has the risk of dichromate staining
unless you expose very carefully. When I coat the paper with unpigmented
gum + dichromate mixture and expose it 30 secs without the negative +
contact printing frame combo (my normal exposure with negative and
contact printing frame is 360 secs / 6 mins. In other words: I expose
the unpigmented gum + dichromate mixture ~ 3.5 stops less when
sizing...), I get a slightly greenish / grayish surface (very slight and
subtle, but you can see it clearly), not paper white. Probably I should
expose less in order to get rid of the stain (or reduce it further) but
if I do so, I may get suspicious about the effectiveness of the sizing.
Therefore, I size with gelatine and harden in formalin. (BTW, I should
admit that: I never tried to use paper sized in that manner - I mean for
gum printing, I didn't like the cyanotypes I've made on paper sized with
gum dichromate - and dumped that method when I saw the stain + my bad
experience with Cyanotype... I also didn't tried to establish a
non-staining exposure time - I guess I was lazy back then).

Regards,
Loris.

-----Original Message-----
From: Yves Gauvreau [mailto:gauvreau-yves@sympatico.ca]
Sent: 15 Aralık 2005 Perşembe 14:31
To: alt-photo-process-l@sask.usask.ca
Subject: Re: glut

Hi,

out of curiosity, would there be a "problem" sizing with gum instead of
gelatine especially if you intend to do gum printing later???

Yves

PS Aren't we suppose to sent our message in plain text...
Received on Thu Dec 15 07:14:44 2005