Regards,
Jonathon Russell<
Hello Jonathon and others !
At first I have to clear that I donīt know if my modified PMK version (I
call it AB C+ - Pyro) is similar to Rollo Pyro from B&S.
But Iīm working with ABC+ Pyro since 1996 after I had bad results in PMK on
my HP5+ negs. I modified the developer because
the negatives showed terrible base fog and weake impressions. The
relatively long developing times for N+ and N++ and the
resulting strong staining of PMK let me " create" my own recepture.
At first I simply cut the developing times by concentrating the stock
solution A with metol and pyrogallol, second by doubling the amount of part
A and B in the working solution.
As an organic antioxidant and sub-developing reagent I added ascorbic acid
(vitamin C) and for clearing the base fog I added a
small amount of Potassiumbromid ( sorry Mr. Hutchings but thatīs really
important).
I use this formula since 1996 at all my 8x10" negs for platinum/palladium
printing but also for silver gelatine enlargments with best
results.
I also published this formula on this alt-photo list a few month ago and
some other photographer had also good results with it.
ABC+ Pyro (only a modest modification of PMK)
Part A:
400ml dist. Water
7,5g Metol
10g Sodiumbisulfit
75g Pyrogallol
5g L(+)-Ascorbic acid
7,5ml Potassiumbromid solution (10%) (equal 0,75g)
2,5g EDTA-Na4
add water for 500ml
Part B:
950ml dist. water
150g Sodiummetaborat .........(in double water against
recrystallisation)
Working solution:
2 Parts A + 8 Parts B + 100 Parts water
Developing times (N normal) at 22°C (rotation):
FP4+ (6,0 min)
HP5+ (6,5 min)
Lotus NP22 (6,0 min)
TMax100 (6,5 min)
Another advantage of this formula is that you can reach real film speeds of
nearly all types (FP4+ is 125 ASA, HP5+ is 400 ASA)
I hope this will help
nice greetings from austria
Harald Leban
hlebanphot@compuserve.com
platinum work :
http://www.aperture-photo.com/site/platinum/leban/index.html