Re: POP and D-min, D-max & DR

About this list Date view Thread view Subject view Author view Attachment view

From: Ryuji Suzuki (rs@silvergrain.org)
Date: 07/07/03-02:18:39 PM Z


Hey Ray,

Are you really making Albumen-like material? (I don't know the
product you refer to but the name suggested someting to me)

I think printing out can be done with many types, from non-emulsion
salted paper, collodion-type coating, etc. but I guess you are a
silver gelatin guy, so I suppose you are making emulsion.

I never particularly looked for POP emulsions but what I remember is
that they are pretty similar to a pure chloride contact printing paper
emulsions, but with huge excess of silver nitrate. I've seen formulae
where single jet is used. The kettle is acidified gelatin dispersion
with only a small amount of NaCl where the jet is silver with citric
acid. Such a process would give minimum ripening but I suppose the
process could be modified to be ammoniacal to give some ripening if
desired. Emulsion isn't chemically sensitized. Such an emulsion can't
be washed (or you lose excess AgNO3) so you have to coat it
immediately after making - no remelting. Pretty inconvenient, but I
suppose excess silver is the key.

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

About this list Date view Thread view Subject view Author view Attachment view

This archive was generated by hypermail 2.1.5 : 08/07/03-03:34:49 PM Z CST