Pyrocat and Low Lighting Conditions with High SBRs

[Francesco]

I have had some failures using Pyrocat HD on Efke PL 100 on low lighting conditions which exhibit relatively high contrast ranges. For example, an EV range of 4 to 8 or 7 to 11. Any suggestions on how to deal with such low lighting conditions and wide SBRs using Pyrocat HD?

 

[Francesco]

Addendum: It appears that my negatives are too thin. The problem in my opinion is underexposure. What is the difference in stops between the following: SBR = 9, the first scene registers and EV range from 11 to 15, the second scene 7 to 11. Would such a difference necessitate a different development time in Pyrocat?

 

[clay]

What film are you using? That will be the single largest factor. T-grain emulsions do not exhibit reciprocity departure to the same degree as do traditional films. What exposure times are you using? Anything over a second, and an exposure AND development adjustment will need to be made. So, if you can give us the film type and the indicated exposure time, we'll probably have a much better idea on what may be happening.

 

[sanking]

Addendum: It appears that my negatives are too thin. The problem in my opinion is underexposure. What is the difference in stops between the following: SBR = 9, the first scene registers and EV range from 11 to 15, the second scene 7 to 11. Would such a difference necessitate a different development time in Pyrocat?

There would be no difference in development times in these two situations, either eith Pyrocat-HD or with other developers, unless you happened to get into the reciprocity range with the lower lighting situation. In that case you would have both an exposure issue, and a compensation issue that might have to be taken into consideration in development due to reciprocity correction. Reciprocity will vary a lot between films, as you no doubt know.

 

[Francesco]

Film is Classic 200 and Efke PL 100 8x10. Exposure times are half a second to two seconds. Not much reciprocity adjustment here I think.

 

[clay]

If my indicated exposure were 2 seconds on one of the older style emulsions, I normally would give at least 4 seconds actual exposure.

 

[Francesco]

Thanks Clay. I will try this out ASAP. Why do you suppose the older style emulsions exhibith such recip failures so early on?

 

[clay]

I think the thicker old style emulsions exhibit this because of a 'threshold' phenomena, where below a certain amount of light, the light senstive compounds in the emulsion are just not activated. My rule of thumb is [indicated->actual] [2->4],[5->20],[10->50],[30->3-1/2m] for old style films. Your mileage may vary depending on the developer and the film type. Now when I am in those situations, I fall back on the Phil Davis BTZS palm pilot expodev program's recommendation, and so far, it has been right on the money.

When you are in situations with long bellows extensions, reciprocity problems and filter factors, I have found that little program to be invaluable. At first I felt like a wimp using this 'crutch'. But then when my negs kept coming out of the wash exactly like I wanted, I decided to just be a wimp and make my life easier when it comes to printing. And anyway, is it any more unmanly than setting your 35mm to 'A' and then shooting away? Definition of a reasonable man: "A reasonable man can find a reason for anything".

 

[Ole]

Francesco, Clay is right. With EFKE PL100 you do need to compensate for reciprocity failure at times over about 1/2 second.
Your contrast range should be easy to fit on the film with Pyrocat-HD; I usualy don't start thinking about compensating developers until the range is like EV 3 to 14. This is surprisingly common aroud here - my bridge photo measured EV -2 to 17. I didn't develop that in P-HD...

 

[Francesco]

Thanks Ole. It is when the ranges are at lower EV numbers that my problems have arisen. Those same ranges at higher numbers have not been a problem (e.g. 9 to 16). A -2 to 17 range!

For really wide ranges I use TFX-2 myself.

 

[noseoil]

I've tried to get reciprocity tables for Efke films and have not had any luck. Used the curve for FP4+ and it seems to be close enough to use, but still wondering if there isn't something better. There may be data out there, but I have not found it. If anyone knows of a site where it is available, I would appreciate hearing about it. Thanks, tim