From: Kate Mahoney (kateb@paradise.net.nz)
Date: 09/05/03-02:47:18 PM Z
----- Original Message -----
From: "Ryuji Suzuki" <rs@silvergrain.org>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Saturday, September 06, 2003 1:26 AM
Subject: Re: coating method
> From: Kate Mahoney <kateb@paradise.net.nz>
> Subject: Re: coating method
> Date: Fri, 05 Sep 2003 18:27:51 +1200
>
> > Yes, dry plates that have been coated with a gelatine/chrome alum
> > mix previously. I use Tetanal "work"emulsion, but I'm keen to try
> > multicoloured gum on glass in the future.
>
> I see... so you are not using it in camera.
No, I'm enlarging onto it.
>
> > I find too viscous an emulsion is difficult to fix. I apply two
> > coats of runny emulsion.
>
> Viscous gelatin dispersion would give you superior dry strength as
> well as superior response to hardening agent. I don't know why your
> fix time becomes that long... maybe coating too thickly?
Yes, I'm sure that's what it is - heating the glass helps a lot, stops the
emulsion from coagulating while I'm applying it.
>
> > I always harden in the stopbath, for which I use water and Ilford
> > film hardener. I've had a lot of trouble with lifting and frilling
> > even with cold baths.
>
> If lifting and frilling is a problem during processing, I think
> hardening at coating or hardening before development should help.
Great, I'll try it :)
>
> Unhardened gelatin is very easy to get swollen a lot in developer even
> at 20C, and this increases the volume of the gelatin. But the gelatin
> should stay in contact with glass substrate, meaning that the gelatin
> shouldn't swell too much. I'd go with an aldehyde hardener, probably
> with some glycerin.
The glycerin is for what purpose???? Can you recommend an aldehyde hardener,
otherwise I'll just use formaldehyde as the easiest to get - I have a fume
cabinet btw.
>
Kate
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