Re: Gum problem(s)

Judy,

For my first tries with the photoflood I used it in a 10" reflector and the
paper got a bit warm if not hot but for this last try I used it without a
reflector and there was insignificant warming as far as I can see.

To show that what I did may not be as bad as I suggested I could join a scan
of my last try if this is aloud here. (I'll send it directly to you so you
can see for yourself)

Here are the details of setup I used with some observations and some
comments.

5 ml of Gum solution (1 table spoon of powder with 30ml of deionized water
which is about a 1:2 ratio)
1 to 1 1/2 cm of pigment paste I mix from dry pigment and photo flo 200 (I
didn't measure but I didn't use more then 1.5ml)
5ml of saturated potassium bichromate solution ( used good water here again)

I coated very thinly a 5" x 7" Fabriano Aristico extra white ( grana satina
hot pressed) 100% cotton and 140/300. I could add that my coating wasn't
that uniform either I think it shows in the image I've attached.

Exposed 20 minutes under a #2 photoflood light (no reflector).

Develop in 3 bath at ~ 68F ten minutes in each (with no agitation except for
a peek at about 5 min for the first 2 baths).

I notice that the pigment/gum in the area outside the step tablet was
extremely soft and I removed it all by rubbing my finger as delicately as I
could. I assume I shouldn't do that in the future. One may say that's very
good, you got 7 to 9 steps showing to which I would reply the separation
between those step is close to inexistant and we can hardly read the number
or text because of the texture and staining.. If this was a delicate flower
with lovely details, only my imagination could tell and this is certainly
not what I was expecting but I also saw in my reading that this could be
helped by printing multiple time. Assuming the pigments don't get into the
paper the texture would possibly improve as well.

Thanks for your time and efforts
Yves

----- Original Message -----
From: "Judy Seigel" <jseigel@panix.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Thursday, November 17, 2005 11:48 PM
Subject: Re: Gum problem(s)

>
>
> On Thu, 17 Nov 2005, Yves Gauvreau wrote:
>
> > 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.
> >
>
> 20 minutes under a photoflood could cook (ie insolubilize) your emulsion,
> unless you aim a fan on it. For what it's worth,in my experience,
> photoflood is lousy for gum...
>
> My suggestion would be use a 21 step wedge, because what you're doing now
> is by guess & by golly. Then you make the negative to correspond to the
> steps you are actually printing... But measure your emulsion carefully --
> by drops of gum, of water & of dichromate solution, plus weight of paint.
> You don't have to do this perennially, once you get the ballpark you can
> estimate, but now you're flailing. Suggestion: start with 20 drops gum, 20
> drops dichromate & 20 drops water, and a pea sized bit of a nice easy tube
> color -- what brand have you got?
>
> For the purpose of zeroing in on exposure & formula, opaque or transparent
> paint is fine -- but... it's got to be a paint that works. Some in some
> makes can be exceedingly difficult (as I've always found, in most combos,
> carbon black). Which are you using?
>
> J.
>
>
> > 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.
> >
> >
Received on Fri Nov 18 07:57:42 2005