RE: Gum problem(s)

But isn't photoflood a tungsten light source? There would be very little uv
output then, a lot of heat though.....when ever I've done copywork under
photofloods, I've used tungsten film.
Kate

-----Original Message-----
From: Katharine Thayer [mailto:kthayer@pacifier.com]
Sent: Saturday, 19 November 2005 4:31 a.m.
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Gum problem(s)

Yves,
Thanks for description.

Okay,, this sounds like (1) pigment stain (not clearing in masked
areas) and ... (2) ... hmmm, I'd need to see the print, I think. Your
description of not much pigment in exposed areas sounds like
underexposure, but 20 minutes under a photoflood is a very long
exposure. My exposures are from 1 to 5 minutes with the same kind of
light; most exposures are 2 or 3 minutes. But if you live in a very dry
climate, you may need a longer exposure, as there is almost a vertical
inverse relation between humidity and time required for hardening.

Katharine

On Nov 17, 2005, at 6:30 PM, Yves Gauvreau wrote:

> Hi all,
>
> I tried a few variants in the pigment / gum ratio and coated to
> different
> tickness directly on paper using various exposition times. None of the
> combination I've tried cleared to the paper in masked areas. Also I
> tried
> this with one dark brown watercolor paint tube and one using a dry
> pigment
> (dark brown also). I use a 1:1 ratio of pigment/gum and saturated pot.
> dichromate solution.
>
> I also notice the unmask area don't hold much if any pigment either.
> It's
> like some pigments get into the paper causing a noticable darkening and
> almost none stays on top of the paper in insoluble gum. My last
> attempt was
> 20 minutes exposure under a #2 photoflood light.
>
> Any suggestion on what is the problem(s) and what I should try next?
>
> Thanks
> Yves
>
> PS Both pigments I used seem to be of the opaque type if this could
> help.
>

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