Re: The Film Developing Cookbook (esp re: PMK)


William Laven (wmlaven@platinotype.com)
Fri, 19 Feb 1999 12:09:24 -0800 (PST)


I just bought the book yesterday and glanced through much of it and focused
(sic) on the chapter on Tanning developers being a new devotee of Pyro PMK.

There are several comments they made which bear on PMK in Jobo drums which
I thought were interesting.

One, they propose a very conservative formula for developer volumes (p.31),
specifically, 500ml developer/8x10 for dilute developers like PMK and
Rodinal. With the Jobo Expert 3005 (used by many for 5 sheets of 8x10) that
would mean 2500 ml of developer which far exceeds the maximum possible
volume of 1500ml. How much developer do most people use in their Jobo
Experts? I recently tried to develop 5 sheets with two batches of 500ml of
developer (ie each batch for half the development time) and the stain is
much weaker than when I use a liter for each bath. Probably too much
oxidation with so little volume.

They also warn that "continuous agaitation interferes with the formation of
sharpness-enhancing edge effects. Because continuous agitation exaggerates
highlight development at the expense of shadow development it also results
in lower speed and a shorter tonal scale. One way of compensating for this
is to use a more dilute developer. Whatever developer you use, dilute it
with at least 30% more water and increase your development time." (p.34)
Any comments re:any developer or especially PMK?

They also comment specifically on PMK and Jobo in terms of developer
oxidation, claiming the rpms are usually too high and that the motor is too
weak when the drum is filled to capacity. (p.77) Have others really had
this problem. My motor seems to do fine.

They mention three "solutions" to the developer oxidation. 1) Splitting
development time into two halves, each with fresh developer. 2) add 0.3g/L
of sodium sulfite to working solution. 3) use 30% more stock solution A
when making developer. No mention of Rollo Pyro. What do people think of
their third idea (added Sol A) which they claim is the best alternative?

In the chapter on tanning developersThey also claim the post-fixer bath of
used developer or sodium metaborate is probably unnecessary if one has used
an alkaline fixer unless the wash water is acidic.

In all, there are some interesting ideas re:PMK and Jobo, but some of them
seem untenable or ungrounded. Any comments re: their fears and proposed
solutions would be interesting to discuss.

There is also quite a bit about pyrocatechin as superior to pyro. Any users
out there with good formulas for contemporary films and results worth
mentioning?

Bill

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