Any thoughts on J&C Classic 200, dilution 0.5:0.5:100, SBR = 9, 6 mins? Would such a negative and dilution combination still allow it to be a candidate for PtPd? Azo?
Just experimented with Pyrocat HD 3:3:600 ml dilution on Classic 200 rated at 200, for 6 mins and 12 mins. Result: barely discernible rendition of the scene. For all intensive purposes the scene, which had an SBR=9, did not develop. All I got was very close to clear film. Can anyone explain whether such dilutions are too weak or that my times were too short?
A dilution of 3:3:600 of Pyrocat-HD is not too weak but you will need very long develoment times. And you must be sure to start with enough developer for the film. I sometimes use stand development for 120 roll films such as FP4+ and TMAX 100 with a 2:2:400 dilution but development times are very long, up to 45-60 minutes. I use a minimum of 16 ounces of developer per roll of 120 film.Quote:
Originally Posted by Francesco
You have have also made a mistake in metering the scene but for sure your develoment times are way too short for this dilution.
Let me add to the previous message that stand develoment is more appropriate for printing with reglar silver gelatin papers than with AZO. I doubt very much that you would be able to get a high enough CI for AZO using a 3:3:600 dilution of Pyrocat-HD with stand development.
I am really not sure what you hoped to achieve with this extreme dilution, assuming the final objective is AZO printing. My tests would indicate that you could handle an SBR of 9 with the 2:2:100 dilution of Pyrocat-HD with a development time of around 7-8 minutes. This should give you a negative with a DR of about 1.3 (Visual) or 1.6 (Blue) that would be just about right for AZO.
My metering method: I use a 1 degree spot meter to measure the Exposure Values of those areas in the scene important to me. The lowest and highest EVs give the scene's SBR. In this particular case where the SBR = 9, the lowest EV value was 10 and the highest 14. I exposed at f. 45, 2 seconds (I would think that this is quite a reasonable amount of exposure). It was a very sunny day and the scene was a cluster of trees in a dense forest. It is that time of the year when I am inspired to take bright sky scenes together with deep shadowy tree formations.
It seems that I have been encountering wide SBRs of late. Over the last month or so I have typically been developing negatives with SBRs of 9 and 10. Twice I have tried a negative with an SBR of 11 and 13. Maybe I measure the scene overzealously while at the same time overestimating the exposure range capabilities of the film.
As regards the extreme dilution, I was just curious as to how effective or potent PYROCAT HD would still be (target negative = silver printing). I am quite happy with the 1:1:100 and 2:2:100 dilutions, which are quite economically already. Just pushing the envelope even further on such a versatile developer.
An SBR of 4 would imply an extremely low contrast scene. The scene I have referred to above was definitely contrasty, much more than normal. Even without using a meter I can observe (and remember, as I shot this scene yesterday) that there was a significant difference between high and low values.
As regards my technique, I have been using this metering method since taking a BTZS workshop back in 1996. It has not let me down yet. Recently I have decided to switch to Pyrocat HD and Efke and Classic. But rather than play with a densitometer I thought it would be more fun to take actual pictures (2 to 4 shots same scene, same exposure) and experiment with dilutions and times. This is why I have been interested in specific instances of high SBRs (plus the fact that Stockholm archipelago is quite contrasty during clear, sunny days). I initially started with extensive BTZS tests for TMX and HP5. Using this metering method together with the data and charts for development times and SBRs matches well the rule of thumb ("...plus 5") that you mentioned.
I just do not see how what I saw yesterday translates into an SBR of 4. Not with that kind of sunlight.
Hmm...seems to me you have modified the BTZS method to fit your particular way of working. Other than using Phil's formula to translate "zone" readings into SBR readings I have not heard of another useful method.
Is this how you ar egtting your SBR readings? by converting zone readings with Phil's formula?