From: Sandy King (sanking@clemson.edu)
Date: 01/23/02-01:00:33 PM Z
Others may want to elaborate on my response as your question is both
simple and complex.
Basically, a developing out process is one in which a latent image is
formed during exposure but does not appear until it is developed out
in a chemical bath. In a printing out process the image actually
forms and is visible during exposure. Virtually all modern silver
papers are DOP but in the past many commercial papers were POP. Of
the alternative processes commonly used today POP processes include
albumin, salted paper, vandyke, and ziatype, while DOP processes
include carbon, traditional kallitype, traditional pt/pd, cyanotype
and gum bichromate.
The fundamental printing difference between a DOP and POP process is
that the latter is self-masking, that is, with increasing time of
exposure the first areas that develop image density - the shadows -
begin to mask themselves, and the longer the exposure the less
contrast one will observe in the print. With a POP process the DR of
the negative must be balanced to the tonal scale of the process or it
will be impossible to make an optimum print. If the DR of the
negative is greater than the ES (exposure scale) of the process the
result will be a flat print with muddied shadow and mid-tones; if the
DR of the negative is less than the ES of the process the highlights
will develop before you obtain good density in the shadow.
Sandy King
>Hi,
>
>This is basic question, so I apologize in advance
>if it is a very silly one.
>
>I do not full understand the distinction between
>the developing out platinum process and the
>printing out platinum process (other than the
>obvious one). Occasionally I will read a
>description that assumes the reader can infer
>which process was used.
>
>So, what are the advantages of one over the
>other? Do some printers use both? Are the
>chemistries very different, etc.
>
>Thanks in advance,
>Paul
>
>
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