Re: [APML]: Tech Pan Problem

[aa6g@aa6g.org (Chuck Vaughn)]

>Is this older, stored Tech Pan  ?  I've seen this when older frozen
>emulsions have been used ...

I don't know how old it is but I've never noticed new film I've had for
a few months to be worse than freshly hypered. Yes, I store it in the
freezer.

>Are these frequent ? or just once in awhile ?

This is not a problem limited to myself. Robert Bickel and Bob Townsend
are experiencing the same thing just as I described. The more sky fog
the negative has the worse the problem. Strangely enough a negative with
little sky fog and a dense object does not exhibit the problem. I know
this sounds weird but I've had several hundred negatives for a sample.
It's pretty consistent with lots of sky fog.

>I use very dilute stop bath ...  about a 1% solution ....  I see a small
>pinhole like flaw every now and then, but nothing to get me too upset ...
>strong stop bath is usually the culprit for emulsion pinholes or the
>use of old emulsions ....

All three of us use no stop bath at all but we do use the same fixer. Bob
hypers his own 4x5 TP and develops in D76 only.

I'll give Joe's suggestion a try.

One more thing...and maybe I'll make this a separate post. Why are highly
sky fogged TP negatives more grainy than lightly sky fogged ones? This
is another thing that makes no sense to me at all.

Thanks,

Chuck  <aa6g@aa6g.org>