>I used type 55 very early in my photo carreer, so I'll have to do a little
>guessing here. In general, it didn't give me enought contrast for
>alt-process printing. Most alt-process methods require a negative with
>much greater contrast range than silver gelatin. Extending the
development
>time in the package didn't seem to help much.<
Increasing both the exposure and the development time produces respectably
long range negatives for platinum. As I am in the process of checking
this out I would not like to say for the moment precisely how much of each
produces what kind of density.
As to the zone system. it does not really apply as it is designed for the
production of negatives for printing onto develop out silver gelatine
paper which requires a negative with a smaller density range than the print
out processes. Greater exposure and development times are needed for many
alternative processes. One is thus thinking in a different language.
Terry King