From: Clay (wcharmon@wt.net)
Date: 12/04/02-06:05:15 AM Z
On Tuesday, December 3, 2002, at 11:36 PM, Scott Wainer wrote:
> Hello all -
>
> I'm hoping someone out there can help with my problem.
>
> Problem:
> After reading "The Book of Pyro" and visiting www.unblinkingeye.com, I
> recently switched from Ilford ID-11 film developer to Pyrocat-HD with
> the hopes of getting negatives that have better tonal seperation, are
> sharper, and have less grain. I am currently performing film speed
> tests with Ilford Delta 400 (4x5) which I will use to create enlarged
> negs (via Liam's reversal process) for contact printing. I believe
> that I am getting excessive general fog; causing extreamly slow film
> speed results.
>
> Processing:
> I chose 15 minutes as a starting time and tray developed (with gloves)
> at a dilution of 1:1:100 (see below for formula); agitating for 15
> sec. every minute. I used a water stop (2 min.) and fixed (2 min.) in
> TF-3 Alkaline Fixer without Sod. Sulfite. I then returned the film to
> the developer for 2 min. without a rinse, washed for 20 min., and
> dried.
>
> Having a B&W densitometer, I could not get an accurate density reading
> from the stained film. Using the process for estimating negative
> density without a densitometer found in the Ansel Adams Guide : Basic
> Techniques of Photography, I did the following:
>
> 1. Print a very light tone using a unexposed, undeveloped piece of
> film cleared in fixer. I used the densitometer to measure the density
> of the print which I recorded along with the time (A) to make that
> tone.
>
> 2. I then printed an unexposed piece of film developed in Pyrocat-HD
> to the same tone as in step 1, using the densitometer to ensure the
> density of the print matched that the original. Again, I recorded the
> time (B) to make that tone.
>
> 3. Next, I printed a piece of film exposed for Zone I and developed in
> Pyrocat-HD to the same tone as in step 1, using the densitometer to
> ensure the density of the print matched that the original. Again, I
> recorded the time (C) to make that tone.
>
> 4. Finally I divided the times B & C by the time A to come up with the
> ratio for steps 2 & 3. I then compared the ratios for steps 2 &
> 3 against the Exposure-Density chart.
>
> What I came up with was that the density for base+fog (neg in step 2)
> was approximately 0.22 and the density for exposure (step 3) was
> approximately 0.24. Assuming I need a density of 0.10 above base+fog
> for zone I, I would have to rate my film at EI 100 for a 400 speed
> film (a loss of 2 stops).
>
> Question:
> The newer version of Pyrocat-HD uses a 100% soln. of Pot. Carbonate -
> the older version used a 10% soln. of Sod Carbonate. Per Anchell's The
> Darkroom Cookbook, Pot. Carbonate is stronger than Sod. Carbonate -
> needing 0.90x the weight for subsitution. According to The Book of
> Pyro, pyro combined with a strong alkali (higher ph)increases base
> fog. Should I revert to the older formula? I also read that Ed
> Buffaloe (unblinkingeye) used a 10% soln. of Sod. Hydroxide (even
> higher ph). Does a 10% soln. of Sod. Hydroxide have a lower ph that a
> 100% soln. of Pot. Carbonate?
>
> Plea:
> Pleasssssssse, somebody set me straight. I will have to go back to
> ID-11 (sigh) if I can't straighten this out. I want it all - better
> tonal seperation, sharpness, and less grain at somewhere close to the
> manufacturer's ISO/ASA.
>
> Thanks in advance from a newbie,
> Scott Wainer
>
>
> The Pyrocat-HD formula I use is:
>
> Stock Soln. A
> Sod. Bisulfite 1 gm
> Catechol 5 gm
> Phenidone .2 gm
> Pot. Bromide .2 gm
> Distilled Water to make 100 ml
>
> Stock Soln. B
> Pot. Carbonate 100 gm
> Distilled Water to make 100ml
>
> Diluted 1:1:100 with distilled water
>
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