1. I do not think and did not say that pyro = compensating developer.
In particular, I did point out one difference although I did say that that
particular difference might have more significance in silver printing than in
alt. process. Please remember the pretext (or the background why we started
this thread). This is not a general photography list where we talk about pyro
development / effects in general.
We started the discussion because we were talking about using pyro to make
enlarged negatives for platinum printing, and some of the beautiful effects
that were described include the increased density range, edge enhancement,
acutance, and improved highlights --- ok, I can take "improved highlights" now
but still cannot make myself say "improved highlight separation." :) There
is a difference, but hopefully we won't argue about that now.
The whole point that I was trying to say was that the effects under discussion
can caused by two distinctive actions: the staining increases the overall
density range, but it is the compensating effect that increases edge
enhancement (macro and micro) and the improved highlights
Maybe everyone already knew about that before I posted my message. If so,
great! but if not, I thought that would be useful for anyone doing more
experiments in making enlarged negatives, regardless of whether it is in pyro
or regular compensating developers.
Of course, there may be more than one visual and / or measurable difference,
but those were not really discussed in previous threads, so again, my point
was the effects that we were *discussing* can be explained in terms of
staining and compensating.
2. I do not think and did not say that compensating developers are better than
pyro developers.
Some comments came out after my posts and talked about which is better or that
we shouldn't call one thing better or how we should finally judge better. If
you consider that a separate, new thread, that is fine; but it shouldn't have
come out of my message because if you read my post again, you will find that I
DID NOT, NEVER said that compensating developers were better than pyro.
I guess my tone did imply that I think the effects *under discussion* can be
achieved by compensating developers, but that needs some (maybe lots of)
testings and measurement. I stressed the *under discussion* because I cannot
say that for *all* effects of pyro, espeically since they were not mentioned
yet.
3. I do not think and did not say that you could just take a compensating
developers and produce negatives that are the same as those developed by pyro.
Definitely not! Compensating developers can give you the effects that we
discussed, but for one thing, if you just follow some standard formula, then
the effect is to produce a nicely compensated negative for silver printing. As
such, the negative will have too low a density range to be used for platinum.
But if you experiment with compensating developer (careful control of
agitation, amount of dilution, and the total volume in the tray / tank), than
you should achieve the effects that you want. The question is whether you have
the time for these tests, and that leads to my summary.
*** SUMMARY ***
In summary (I have actually said this in my post also), that if it so happens
that a particular pyro formula give you *everything* that you need for
platinum printing (or cyanotype as another person asked, or whatever process),
then fine, stay with it.
But if it doesn't happen so, and you need to test and tweak it here and there,
then I think it is useful for you to realize the different (staining and
compensating) actions of the developer. I believe that will shorten your
tweaking time because you consciously know what you are after.
I admit that my implied suggestion is that if you are going to test and tweak
anyway, you might be able to just do the same in silver especially if you are
already more familiar with regular developer (but I DID NOT suggest which one
was better).
Dave
PS: Some wrote me on list or off list with particular questions / objections.
I will get to that later. Sorry about the delay. :(