Re: A little gum test

"What's really interesting is that I NEVER use direct sun - all my prints
are exposed in a corridor with high windows which reflects a lot of light -
but
I think the UV must be high because digital shots in the area always come."

If your windows are closed, there will be practically no UV light at all.
This might suggest you actually expose your gum layers at - visible -
blue/violet radiation (which in fact would not be too surprising given
dichromated
colloids are sensitive from UV - ~550 nm)...

Martin

----- Original Message -----
From: "Kate Mahoney" <kateb@paradise.net.nz>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Monday, December 15, 2003 8:49 PM
Subject: Re: A little gum test

> What's really interesting is that I NEVER use direct sun - all my prints
are
> exposed in a corridor with high windows which reflects a lot of light -
but
> I think the UV must be high because digital shots in the area always come
> out very blue on daylight setting. You would hardly think that 4 min
> exposures in diffuse light would be overexposed!
>
> Kate
>
> ----- Original Message -----
> From: "Katharine Thayer" <kthayer@pacifier.com>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Monday, December 15, 2003 1:09 PM
> Subject: Re: A little gum test
>
>
> > Kate Mahoney wrote:
> > >
> > > Hi Mark, Less contrast with the saturated solution was
> > > postulated....so I'thought I'd give it a whirl. I have been getting
> > > rather flat prints so this is good news. The results (to me) show some
> > > of the reason why I've been having some trouble with this technique -
> > > obviously too much amm.di. I think the reason why the tones are better
> > > is that mostly I've just been overexposing with the amm. di. at the
> > > more concentrated level...
> >
> >
> > Thanks Kate, this provides some confirmation for a suspicion I've had
> > for some time, that when people say that saturated ammonium dichromate
> > prints flat, perhaps what they really mean is that they overexpose when
> > they print with saturated ammonium dichromate. I have never observed
> > that saturated ammonium dichromate prints flat when properly exposed.
> > That not only the shadows but the highlights were blocked (I'm assuming
> > you mean after a reasonable development time) suggests that the problem
> > was related to significant overexposure, as you suggest above, rather
> > than to the contrast range of the saturated dichromate per se.
> > kt
> >
>
>
>
Received on Mon Dec 15 23:02:04 2003