kateb@paradise.net.nz
Date: 07/16/03-11:09:14 PM Z
Quoting Katharine Thayer <kthayer@pacifier.com>:
> kateb@paradise.net.nz wrote:
> >
>
> > For me, it was always that I'd underexposed, and it can also be
> related to the
> > thickness of the coating. Unless you're applying a measured coat of
> emulsion
> > with a rod in a defined paper area, you're always going to get a
> variation -
> > this could make a slight and undetectable difference to exposure time,
> with the
> > result that some prints will not expose as well as others. If the
> coat's too
> > thick, it will just wash off because the gum next to the paper surface
> won't
> > have received enough light to harden. Of course if you have a thicker
> emulsion
> > layer there will be more pigment (physically)in the thicker coat than
> in the
> > thinner one - if you see what I mean.
> >
>
>
> Kate's points are all excellent. I might say one thing a bit
> differently, although we may well be saying the same thing in different
> ways: to me the issue of exposing all the way through to the paper and
> the issue of a too-thick coating flaking off are two separate issues.
> There is a range of coating thickness within which it's simply a matter
> of exposing enough to harden the gum all the way through to the paper,
> (and BTW this is true even of very thin layers; even the thinnest of
> layers looks a lot deeper to the ions and photons involved than it does
> to us). But beyond a certain thickness or pigment concentration, you
> could expose all day and that stuff is still going to flake off as soon
> as it hits the water.
> kt
Too true, Katherine, I had that problem as a raw beginner! I may have muddied
the issue a bit - sorry!
>
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