Re: coating method

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From: Ryuji Suzuki (rs@silvergrain.org)
Date: 09/05/03-10:02:46 PM Z


From: Kate Mahoney <kateb@paradise.net.nz>
Subject: Re: coating method
Date: Sat, 06 Sep 2003 09:22:37 +1200

> No, I think the lifting is the emulsion layer as there seems to always be
> hardened sub left on the plates.

Ok, then the rest is easy (procedure-wise, same as what I already
said). Harden the emulsion. If the emulsion coat has less tendency to
swell (and thus expand) then it's less likely to lift.

I don't know what gelatin you use for subbing, but silver gelatin
emulsion is basically gelatin dispersion like your subbing material
from mechanical strength viewpoint. So, if you adjust the hardening
and plasticity just right, I don't think subbing is necessary.

I don't think alum is a good hardener to use for emulsion, though, and
I know glutaraldehyde works because that's what I use.

From: Katharine Thayer <kthayer@pacifier.com>
Subject: Re: coating method
Date: Fri, 05 Sep 2003 18:03:13 +0000

> I love this! We were talking about how to measure the viscosity of gum a
> while back; this forced choice method has the advantage of needing no
> equipment or standardization, and is actually fairly good for measuring
> some things, but perhaps may not be a fine enough measure to distinguish
> between different gums. But I like it. Everyone knows what the creamy
> part of risotto is like, and latex paint, and hollandaise sauce.

Thanks for the praise. It could be only easier if Heintz ketchup came
in grade 1 through 5...

One the problem is that... the consistency of creamy part of risotto
varies, depending on whether it is served with meat or vegetables,
whether it uses arborio or carnaroli (which is a cross of Italian and
Japanese rice varietals), etc... maybe Italian people here can
clarify.

> Gum (my gum, anyway) is not as thick as anything you describe here; it's
> more like a good varnish. It would coat a spoon if you dipped a spoon in
> it, but it flows and brushes easily. I can't think of a food that it's
> the same consistency as. Maple syrup, maybe.

Fresh vegetable oil (for cooking), maybe less viscous?

Silver gelatin emulsion may be comparable to this degree of thickness
if diluted with equal part water without hardening but I think
processing may be problematic, Dmax disappointing, and coating tends
to be uneven.

--
Ryuji Suzuki
"Reality has always had too many heads." (Bob Dylan, Cold Irons Bound, 1997)

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