Minimum volume stock solutions Pyrocat HD per film?

[Cor]

Lately I started wondering about the following:

I process 8X10 HP5 +, 2 sheets at the time, in a JOBO print drum, in a JOBO CPE-2 at 22 degC, rotation speed 1.

Although the CPE-2 can run 600 ml solution, to reduce strain on the motor I prefer to run 500 ml max.

I dailed in at 1:1:100 so 5 ml stock A & B per 2 8x10 film.

Although most of my negatives turned out nice most of the times, I got some flat negatives too.

Am I using too little developper stock A?

Thanks,

Cor,

Ps is there a rule of the tumb, roughly, to go from a N to a N+1 expansion ?

[Jan Pedersen]

I think you are on the limit there with 5ml for two sheets.
For TMY400, HP5+ and EfkePL100 i like to use 2+2+100 to avoid long developement time which build up unnecesary overall stain.

With 2+2+100 you could keep your solution at 500ml and have enough part A with 10ml

[onnect17]

According to the information in photoformulary.com, "...use a minimum of 75 ml of the standard working solution per sheet of 4x5 film..."
Not sure if capacity is part of the content at pyrocat-hd.com
Doing the math, you should use 300ml minimun for each 8x10. For 2, 600ml.
So wherever dilution/time/temp combination you decide to use, make sure at least 6ml of stock solution is part of it.
You can double check with Sandy.

[Jay DeFehr]

One option would be to double the concentration of Pyrocat HD, to 1:1:50, which would allow you to use 150ml/sheet, or 300ml total. Of course you'd have to decrease development time to compensate. And there are other developer options. 510-Pyro requires only 1ml of concentrate/ roll or 8x10 sheet, so you could develop 2 sheets of 8x10 in 200ml of 1:100 solution, or 400ml of 1:200 solution.

[Cor]

Thanks for the feedback, guys!

Is there a direct relation between the dilution and the time? I mean I use 12 minutes (not sure, notes are at home) for 1:1:100, what would the time be for 2:2:100 (I know I should , and will test, it would be nice to have a ball park figure).

I am not too afraid for over-development anyway, I shot a few sheets HP5 of low contrast snow scenes in the mist, only 3-4 stops difference, I can start with those,

Best,

Cor

[Lachlan 717]

You won't stress the motor too much.

Yore not actually moving the fluid; you are moving the film and the internal parts through the fluid. Big difference.

The best way to avoid straining the motor is to slow the revolution speed. As force equals mass times acceleration, there will be less "impact" force if you introduce the film and internal parts more slowly into the fluid.

[onnect17]

I read in some other thread about dilution and time being near to a square root relation. So if you double the concentration the new time should be close to T / SQRT(2)



Thanks for the feedback, guys!

Is there a direct relation between the dilution and the time? I mean I use 12 minutes (not sure, notes are at home) for 1:1:100, what would the time be for 2:2:100 (I know I should , and will test, it would be nice to have a ball park figure).

I am not too afraid for over-development anyway, I shot a few sheets HP5 of low contrast snow scenes in the mist, only 3-4 stops difference, I can start with those,

Best,

Cor

[Cor]

You won't stress the motor too much.

Yore not actually moving the fluid; you are moving the film and the internal parts through the fluid. Big difference.

The best way to avoid straining the motor is to slow the revolution speed. As force equals mass times acceleration, there will be less "impact" force if you introduce the film and internal parts more slowly into the fluid.

Good point, didn't think of that, so the strain is than perhaps more on the lift, which is easily overcome by helping the lift a bit with your free hand.

Best,

Cor

[Lachlan 717]

Good point, didn't think of that, so the strain is than perhaps more on the lift, which is easily overcome by helping the lift a bit with your free hand.

Best,

Cor

Yep, and perhaps add a second/third set of rollers to take any stress from the neck of the tank and the connection point.

[Cor]

I read in some other thread about dilution and time being near to a square root relation. So if you double the concentration the new time should be close to T / SQRT(2)

Thanks,

I now recall that rule too..anybody out there can back this up with "real life" data on Pyrocat-HD dilutions 1:1:100 and 2:2:100?


Best,

Cor

[John Berry]

Ps is there a rule of the tumb, roughly, to go from a N to a N+1 expansion ? If I didn't have a time I would use a factor of 1.4 as a start.

[seezee]

FWIW, I've been semi-stand developing 6 sheets of Carestream CSHB at a time in 1010 ml of 1:1:200 Pyrocat-HD with good results. 5 minutes presoak, 60 seconds gentle agitation, 29 minutes stand, 30 seconds agitation, 29.5 minutes stand, stop, fix, wash, rinse. Using an HP-Combi-Plan, but in a darkroom, not as a daylight tank.

Since CSHB is coated on both sides, my 6 sheets = 12 sheets of regular film. Unless I did my math wrong, that's a little over half the recommended minimum: 1010 ml mixed at half-normal dilution = 505 ml standard solution, divided by 12 sheets = 42.08 ml standard solution per 4×5 negative.

Am I missing something here?

[sanking]

FWIW, I've been semi-stand developing 6 sheets of Carestream CSHB at a time in 1010 ml of 1:1:200 Pyrocat-HD with good results. 5 minutes presoak, 60 seconds gentle agitation, 29 minutes stand, 30 seconds agitation, 29.5 minutes stand, stop, fix, wash, rinse. Using an HP-Combi-Plan, but in a darkroom, not as a daylight tank.

Since CSHB is coated on both sides, my 6 sheets = 12 sheets of regular film. Unless I did my math wrong, that's a little over half the recommended minimum: 1010 ml mixed at half-normal dilution = 505 ml standard solution, divided by 12 sheets = 42.08 ml standard solution per 4×5 negative.

Am I missing something here?

The minimum solution, which is about 60 ml of a 1+1+100 solution per sheet of 4X5 film, is the solution necessary to develop film to a given CI when using a specific type of agitation and temperature. Some CI charts are included in an article published first at http://unblinkingeye.com/Articles/PCat/pcat.html.

You are developing with an entirely different protocol so the CI expectations noted in the article would not apply to your results.

Sandy

[seezee]

The minimum solution, which is about 60 ml of a 1+1+100 solution per sheet of 4X5 film, is the solution necessary to develop film to a given CI when using a specific type of agitation and temperature. Some CI charts are included in an article published first at http://unblinkingeye.com/Articles/PCat/pcat.html.

You are developing with an entirely different protocol so the CI expectations noted in the article would not apply to your results.

Sandy

Ah, thank you. I didn't factor that in. So it seems I'm going to have to experiment to arrive at a true minimum solution for my particular workflow.

[Jim Noel]

Your printing method must be added into the equation. If you are printing silver gelatin you can probably get away with your dilution, but if printing Pd or salt you definitely will need more. To get negatives for these processes with the film you are using I use 150 ml of 2+2+100 per sheet.When I tried more dilution, or less quantity the highlights did not develop to appropriate density.
If the Jobo has trouble turning the drum with this load, assist it with the palm of your hand.

[alanbutler57]

I've often used 1:1:100 Pyrocat HD, 600 ml, in a Jobo, developing 12 4x5 sheets at a time. My goal is scanning, not printing, and have had overall very good luck with this, though reading this tread I see I should strengthen the solution.

I looked this old thread up as I move toward a big shoot with X-ray film, so now, I assume, I have to use twice as much developer since there is twice as much emulsion.

My preliminary experiment that gave results I like involved developing only three test shots in the 600 ml drum for six minutes (1:1:100).

So, I did a very simplistic calculation: 12 exposures: 24 emulsions x 70 ml = 1680ml.
But, since the tank only holds 600: 1680/600 = 2.8. So would this indicate 2.8: 2.8: 100 would provide the sufficient amount of developer? If so, reduce development time by about 1/3 which would mean 4 minutes?

I know the proper way to do it is experimentation, but I'm looking for a place to start the experiment and wondering what more experienced folks would suggest.

Thanks,