Re: Sizing paper with gum and dichromate

Kees,

Can you clarify:

1) your first tests used no pigment and were on gelatin-sized BFK paper.

2) Was the paper hardened?

3) Your next tests will duplicate conditions of the first except with the addition of pigment or;

4) ???

Joe

>>> ctb@zeelandnet.nl 12/20/05 11:31 AM >>>
Chris,
I just finished some testing on this subject. I coated several sheets
of BFK (because I had some leftovers). I mixed my gum (homemade from
lumps) and dichromate (saturated pot.di) as I allway do in my
pigmented mix. My usual printing time (UV fluorescent) is 4 minutes.
I coated 6 sheets and exposed for 4, 2, 1 minute and 30 and 15 sec
(all through a piece of blank Ultrafine Crystal Clear film). After
that I left the paper 'develop automaticly' in the water for 1 hour
(as I allways do) and dried. The next day I cleared (at least tried
to) the samples in 5% metabisulfite.

Conclusion: all but one sample had the green stain. The 4,2 and 1
minute exposed had a severe stain. The one that stayed white was
exposed for 15 sec. (i.e. 4 stops under normal). The 30 secs sample
was acceptable allthough stained. Than I coated another one and
exposed for 30 seconds and left this one in the water overnight. Next
morning it looked much better than the first 30 sec. sample.

Next step will be coating these 15 and 30 sec samples with my usual
pigmented mix and look how they behave compared to gelatine sized paper.

-kees

On 20-dec-2005, at 17:06, Christina Z. Anderson wrote:

> Good morning,
>
> I'm late on replying to this post but so it goes at Christmas...
>
> My problem with sizing with gum is this: in order to get the layer
> hard enough to be a suitable size, there will be some discoloration
> with the dichromate that stays in and discolors the whites, in my
> practice. So by experience I agree with kees. If I didn't harden
> to the point of discoloration the layer was too soft. I tried
> clearing with pot metabi but that whole procedure seemed like so
> much more work than just biting the bullet and brushing on a
> hardened gelatin size (e.g. two separate wet and dry cycles). Even
> so, the layer did not prevent staining.
>
> But I would assume somewhere someone out there has luck with this
> method who is perhaps using lighter pigment loads, although my
> assumption is also that since this method, quoted in the books long
> ago, never caught on as primary practice means it just isn't as
> good as a plain old hardened gelatin size. You know what they say
> about "assume", though...
> Chris
>
> Probably a much short time will be enough then. But maybe
> the break even point of hardening enough before the staining starts
> doesn't even exists.
> kees
>
> Loris Medici wrote:
>> Hi Kees,
>> But you will still omit the density of the pigment that way...
>> Regards,
>> Loris.
>> -----Original Message-----
>> From: Kees Brandenburg [mailto:ctb@zeelandnet.nl] Sent: 15 Aral*k
>> 2005 Per*embe 16:26
>> To: alt-photo-process-l@sask.usask.ca
>> Subject: Sizing paper with gum and dichromate, was Re: glut
>>
>>
>> ...But why not standardize things a little bit more and size with
>> gum and expose with your standard printing time through a clear
>> sheet of printing substrate (or film). I'll give that a try this
>> week...
>>
>>
>
>
>
Received on Tue Dec 20 11:21:49 2005