From: Tadeuz Jalocha (tjalocha@netexpress.cl)
Date: 11/17/00-09:30:58 AM Z
Hello Bob and Istvan
Bob, exactly the reasons you give are the ones because i´m starting to
like positives. For alternative processes we generally need large
negatives. I only need to enlarge my positive, and voilá; a big neg. Of
course, you´ll need some care with the contrast, but with Kodak EIR-7
for the neg i get lovely results.
Istvan, there goes a formula i found in the net.
It gives me full speed with Kodak T-Max 100 ( i can´t say anything about
other films because it's the only 4x5" B/W material i can get here )
Border density: 3.0D
Highlights: 0.1D
What i like about this formula, is that it uses Hypo rather than the
very messy thiocyanate.
If you like a thiocyanate formula, try Kodak D-67 (Not D-76!)
1: FIRST DEVELOPER
Water at 125 deg. 750 cc
Metol 2 grams
Sodium Sulfite, Anhydrous 100 grams
Hydroquinone 5 grams
Sodium Carbonate, Monohydrate 60 grams
Sodium Thiosulfate, Pentahydrate 16 grams
Potassium Bromide 4 grams
Cold water to make 1 liter
USE ONCE AND DISCARD.
The original formula says 10 min @ 20 Celsius
I develop 6 min 7seconds @ 24 Celsius in a Jobo Processor ( Draining
time not included! )
This First developer is critical! I get a huge variation with only some
seconds more or less.
2: BLEACH
Potassium Dichromate 9.5 grams
Sulphuric Acid 12 cc
Stock formula:
COLD!!!! Water 750 ml
Poassium Dichromate 100 gr
Sulphuric acid 100 ml ( add SLOWLY acid to water , please be
careful )
Water up to 1000 ml
Dilute 1+19 for use
I Bleach 3 minutes with the second formula. You may replace Dichromate
with Permanganate, wich is less toxic, but costs more. Be VERY careful
with this second stock. This is diluted sulfocromic mixture, it eats
anything organic away like almost nothing else! See other postings about
Dichromate to get a picture about this compound.
3: CLEARING BATH
Water 1000 cc
Sodium Sulfite, Desiccated 50 grams
Agitate for 1 minute.
-------------
You may alternatively Sepia tone the Positive at this stage. ( No
previuos Light exposure needed in that case)
Kodak T-19:
Sodium Sulfide 20gr
Water up to 1000ml
2 min. Take care, this may soften your emulsion exessively!
After Sepia tone, no fixing is necessary.
------------------
Reexposure to light.
I use a 1000w light for a minute or so. Probably overkill. In a
Translucent Bowl filled with Water.
Second development
I use Tetenal Neopress HC 1+31 for 7 min @24 Celsius. ( The only use i
found for this #%$"%$ developer )
Fix and wash as usual.
bmaxey1@juno.com wrote:
>
> >>Is there a feasible procedure to develop my black-and-white negatives
> (Agfa
> >>APX 25)to BW positives?
>
> Formulas abound for doing this, but I prefer not to. The reason is
> simple: once I have reversal processed the film, they are forever
> positives. If this happens, making black and white prints becomes a
> chore, because I then have to create a negative from them, creating extra
> work and a loss of quality.
>
> Bob
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