Pyrocat-hd and film speeds-what's the concensus?

Mike Lyons · Apr 20, 2004

Hi to all. I'm going to give Pyrocat-hd a go and need some help prior to the plunge. It seems that there is a loss of effective film speed, but the reports vary as to how much. I use 4x5 Delta 100, FP4-plus and HP5-plus in an HP combiplan tank taking approx 1000-1200ml of solution.Normally I agitate continuously for 30 secs then 4 inversions on the minute for the remainder. Any suggestions for starting points for film speeds and times for these combinations to help with my tests?
Thanks -Mike

Leon · Apr 20, 2004

I use HD 1:1:100 with gentle agitation for roll film (ie 10 second agitation every 3 mins). I find that most films lose about 2/3 to 1 stop speed this way. Mind you my tests arent overly scientific.

have fun!

Donald Miller · Apr 20, 2004

My experience with Pyrocat indicates that quite often it supports full film speed. The sole exception that I have encountered has been Efke PL 100.

When you ask a question as you did it leaves a great deal unsaid. For instance how one meters (I use incident), where one places their low value exposure if spot metering, whether the image is normally, expansion, or contraction developed. What your negatives are to be used for (contact printing or enlarging).

Insofar as time of development, I would recommend the article that Sandy King wrote and is posted on www.unblinkingeye.com. You will find times for various films. From those times I would extrapolate times allowing for differences in developing procedures.

Best of luck with Pyrocat. I find that it is a wonderfully versatile developer.

john_s · Apr 20, 2004

I have been using a batch of the metol version of Pyrocat-HD (metol amount = 10 times the recommended amount of phenidone). This version is stated by Sandy as being fractionally slower than the standard formula. I'm getting a good solid 320 out of HP5+ in 120 size. I am very pleased with this, since I got barely 200 out of PMK with the same film.

Mike Lyons · Apr 20, 2004

O.K. a bit more detail. I spot meter for the shadows either a typical Zone 1 being a smidge over f=fb values (or 0.08-0.12,) or Zone3-4 being very solid shadow detail with a net neg density in the 0.4 range. I aim for a Zone 8 around a net 1.35 desity. I only print on silver gelatin conventional (fibre or r/c ) variable contrast paper. I realise the stain will bamboozle a white light densitomiter, so I will either adjust by trying the blue channel, or just keep trying until I get negs that fit my needs. Hence the post, your advice has been taken on board and appreciated- it will speed things up for me and I look forward to more of the same.
Thanks again.-Mike
P>S why wasn't I told of this site before? It's fantastic...

gainer · Apr 21, 2004

I use incident light measurement with manufacturer's rating. If I use the spot meter, I multiply manufacturer's rating by 4 and read the significant shadow. I have not found Pyrocat-HD to lose any film speed.

bmac · Apr 21, 2004

gainer said:
I use incident light measurement with manufacturer's rating. If I use the spot meter, I multiply manufacturer's rating by 4 and read the significant shadow. I have not found Pyrocat-HD to lose any film speed.

You multiply it by 4? So basically, HP5+ would be rated at 1600?

clay · Apr 21, 2004

Yeah, but remember you are incident metering the shadows, NOT the brightly lit areas. Same idea as spot metering the shadowed areas and stopping down two stops. I sometimes will just turn the dome facing down, away from the sun or cast a shadow with my hand if I need to find this meter reading.

PJC · Apr 21, 2004

Greetings,

My experience may add some confusion, but this is what I have found...

To date I've only used Pyrocat in a Jobo rotary processor, with constant agitation and largely with 8x10 film at minimum rotation. The 8x10 was always processed with AZO or alt process printing in mind, so the 2:2:100 dilution was used. I have processed some 4x5 and some roll film using the 1:1:100 dilution.

Observations:
1. Film developed in the 2:2:100 dilution can always be metered at the full rated ISO and in some cases even higher. Films used so far are: Efke PL25, PL100, Kodak TMY, Ilford FP4+, Delta 100, Photo Warehouse 125 and Fortepan 200.

2. Films developed in the 1:1:100 dilution and most particularily roll films need to be exposed at a reduced EI. In 4x5, films such as Kodak TMX, Ilford Delta 100 and FP4+ EI 80, but Agfa APX for some strange reason is only EI 32 and I wont develop it in Pyrocat anymore - I can get full film speed from other developers.

3. Roll films typically lose from 1-2 full stops from manufacturer's rated ISO. The only exception I found to this was Kodak TMY, which yielded very close to full film speed.

It should be noted that I haven't conducted sensitometric tests on roll film as I haven't had time and don't use them often. All metering is with a calibrated, Zone VI modified Pentax spot meter, with shadows metered on Zone III.

I hope this helps, but perhaps it accounts for some reports of full film speed and conflicting reports of loss of film speed.

Regards, Pete

sanking · Apr 21, 2004

I have done hundreds if not thousands of very carefully controlled test of Pyrocat-HD for EFS and CI (with reference to other tests using the standard D76 1:1) . Most of these tests have been done with sheet film in BTZS tubes with very gentle rotation, but quite a number have been done with roll film on spiral reels in tanks. All of my tests are exposed with light integrators and developed in controlled environments in which the temperature is held to =/- 0.5ºF.

In all of my tests I have never encountered a situation when Pyrocat_HD did not deliver full emulsion speed, even with the short developing times required for silver gelatin printing. And with AZO and alternative processes, which require a higher CI, my tests have always given much higher EFS values than rated emulsion speed.

And the greatest increase in EFS has always been with the 1:1:100 dilution, which of course is entirely consistent with what one expects in theory.

Sandy King

sanking · Apr 21, 2004

sanking said:
In all of my tests I have never encountered a situation when Pyrocat_HD did not deliver full emulsion speed, even with the short developing times required for silver gelatin printing. And with AZO and alternative processes, which require a higher CI, my tests have always given much higher EFS values than rated emulsion speed.

I should modify the above statement slightly. My tests indicate that Efke PL 100 and Bergger 200 do not deliver full emulsion speed with the 2:2:100 dilution of Pyrocat-HD.

Sandy King

Leon · Apr 22, 2004

I must be doing something wrong then?

mikepry · Apr 22, 2004

Leon,
I wouldn't say your doing something wrong as I need to rate my fp4 at 64 when I print on AZO. One must keep in mind the varibles that can be encountered i.e. light meters, shutters, water temps, etc. I know when I work I do everything the same every time maintaining consistency throughout the whole process. Everything works together as a unit, thus if one thing is not "right" it will affect outcome. On the other hand if that one thing is not "right" every single time in your working system your results will be the same and not necessarily the same as what other people come up with.

sanking · Apr 22, 2004

I am not saying that anybody is wrong. However, it is impossible to make meaningful comparisons of film speed (or speed in certain developes) based on field tests. Such tests involve not only variables in equipment (meters, lens apertures and shutters) but also in method and type of metering. And this is before we even bring the film to the darkroom for development.

I completely eliminate these variable in testing for EFS by contact printing transmission step wedges with a light source timer by an integrator, which results in an error of less than 1/100 of a second with a 0.5 second exposure. Therefore the only variables in my testing are the film, developer (composition and temperature) and method of agitation. Of these the most important is method of agitation and I think many people would be surprised if they realized how even small differences in method of agitation can result in a significant change in contrast, and of EFS since there is a relationship between contrast and effective film speed..

Naturally at some point you have to take the EFS values (what should be consistent from person to person if sound testing procedures are used) that results from testing and validate them in the field to give you a working exposure index, or EI. But EI is personal and can be expected to vary significantly because of the field variables mentioned.

Sandy King

roy · Apr 22, 2004

Leon said:
I must be doing something wrong then?

This does not follow. Rating the film at the speed you do may give you just the negative that suits the process in which you are working and your style of photography or subject matter.

Leon · Apr 22, 2004

... point taken

Jim Chinn · Apr 25, 2004

I have found HD 1-1-100 to provide full film speed for FP4, HP5 (in sheet film) and Delta 100 and TriX in roll film.

Jan Brittenson · Apr 25, 2004

sanking said:
I completely eliminate these variable in testing for EFS by contact printing transmission step wedges with a light source timer by an integrator, which results in an error of less than 1/100 of a second with a 0.5 second exposure.

You're not concerned with reciprocity at 1/2s exposures?

gainer · Apr 25, 2004

Most data on reciprocal trade disagreement is archaic. Howard Bond did extensive testing of a number of films and reported the results in Photo Techniques. I presented his data in a different form in a later issue. In a nutshell, 1/2 second is not significant

Pyrocat-hd and film speeds-what's the concensus?

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