Processing HP5+ and FP4+ in the same tank

Ian Grant · Jan 26, 2025

I regularly process HP5, Delta 100, and occasionally FP4 in the same tank, also EFKE PL25, in Pyrocat HD 1+1 to 100 at 20ºC normal inversion agitation every minute 17 minutes.. The only films I process separately are Fomapan 100 & 200.

Ian

beemermark · Jan 26, 2025

Use Diafine and you can mix any B&W films in the same tank.

GregY · Jan 26, 2025

beemermark said:
Use Diafine and you can mix any B&W films in the same tank.

I can't see the point..... why is mixing films that important?

John Wiegerink · Jan 26, 2025

GregY said:
I can't see the point..... why is mixing films that important?

The only point I can see is that it might save some time.

runswithsizzers · Jan 27, 2025

The opening post does mention:

Tumbles said:
If it's ok, it certainly would speed things along. Pyrocat with minimal agitation tends to have somewhat painfully long processing time.

I wonder what the difference in total development time is, if one development with "minimal agitation" is compared to two developments with "normal" agitation?

GregY · Jan 27, 2025

runswithsizzers said:
The opening post does mention:

I wonder what the difference in total development time is, if one development with "minimal agitation" is compared to two developments with "normal" agitation?

Good thought..... most likely less w normal. Certainly lots of darkrooms have more than one tank ..... i have processed FP4& Tri-X at the same time in tanks side by side.... you just have to be alert & quick.

George Collier · Jan 27, 2025

These are my two prevalent films. After many tests with both films and Rodinal (same dilution for both - 1:48} I discovered by accident that at the same temp, agitation, etc, the times were within 30 seconds of each other, at 73˚F, with no intention of making them the same. Comparisons were based on scanning settings (Silverfast and an Epson V850 Pro) and resulting file dynamic range.
I do them together without issue. (A bit overkill, probably, but I average the time, a 15 second variation for each).

Keith Tapscott. · Jan 31, 2025

The instructions I read for Prescysol developer by Peter Hogan gave a single time for most B/W films.
I believe that Speedibrews Celer Stellar had a single developing time for most B/W films as well.

Both developers are no longer available unfortunately.

pentaxuser · Jan 31, 2025

Keith Tapscott. said:
The instructions I read for Prescysol developer by Peter Hogan gave a single time for most B/W films.
I believe that Speedibrews Celer Stellar had a single developing time for most B/W films as well.

Both developers are no longer available unfortunately.

Not germane to the OP given that both brews are no longer available but I wonder what it was about Prescysol that enabled it to give a single time

I had always thought it was basícally Pyrocat HD. Given what Ian and some others have said maybe Peter Hogan just settled on one time for most b&w films on the basis that this an OK negative that was easily printable ?

pentaxuser

Keith Tapscott. · Feb 2, 2025

pentaxuser said:
Not germane to the OP given that both brews are no longer available but I wonder what it was about Prescysol that enabled it to give a single time

I had always thought it was basícally Pyrocat HD. Given what Ian and some others have said maybe Peter Hogan just settled on one time for most b&w films on the basis that this an OK negative that was easily printable ?

pentaxuser

I believe it was a Pyrocat spin off with some minor tweaks to make the Prescysol developers slightly different.

The standard version had both Metol and Phenidone with a sodium carbonate accelerator while the EF version had if I remember correctly contained Metol and Glycin and possibly an ascorbic acid derivative.

I'm sure someone here probably has the MSDS for these.

Celer Stellar was a developer unique to Michael Maunder.

Tumbles · Feb 3, 2025

I tried it out the other day, and the results seem fine. With the water at room temperature I was getting development times around 25 minutes.

FP4+ looks to have more contrast than the HP5+. Hp5+ looks similar in contrast to the results I got with Tmax 400. I still have to scan them.

FP4+ is on the left, and HP5+ is on the right.

koraks · Feb 3, 2025

As was to be expected, there's a very big difference in the gamma/contrast between the films. Processing them in the same tank was evidently not the optimal solution.
However, underexposure is a bigger problem on both films.

Ian Grant · Feb 3, 2025

pentaxuser said:
Not germane to the OP given that both brews are no longer available but I wonder what it was about Prescysol that enabled it to give a single time

I had always thought it was basícally Pyrocat HD. Given what Ian and some others have said maybe Peter Hogan just settled on one time for most b&w films on the basis that this an OK negative that was easily printable ?

pentaxuser

Prescysol was Pyrocat HD and the original instruction sheet was a direct copy of something written by Sandy King. It was the early version where Part B was Sodium Carbonate. This was confirmed by Les McLean quite a few years ago.

Ian

Processing HP5+ and FP4+ in the same tank

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