Efke IR820 Sheet Film (4x5) in Pyrocat HD

[BarryWilkinson]

I am about to process my first sheets of Efke IR820 Sheet Film (4x5) in Pyrocat HD. As this film is no longer available I am trying to get close results with minimal sheet losses. Can anyone give me a 'ball park' time for this combination. I use Pyrocat HD semi-stand, usually continuous inversion for one minute, the four inversions every three minutes. TIA

Barry

 

[aparat]

My old notes indicate around 13-15 minutes in Pyrocat-HD, 1:1:100, at 20C, with 10 sec agitation every minute. But that was in 120 format in a "normal" contrast scene.

 

[BarryWilkinson]

Thank you aparat, lot's of trial and error seems to be the answer. I will develop for more time than my usual and will post the results here.

 

[BarryWilkinson]

Well, I found that development of this film is not so difficult, as someone said 'as long as it is enough'. I don't know yet if Pyrocat HD is the ideal developer for this film but I do have some images. I tried Pyrocat HD 1+1+100 for 14 mins and 18 mins (agitation for the first minute and four inversions every minute) and do not see much difference with each. There is no fogging in the film margin on either. However I have not bothered to take any density measurements as I underexpose the film by some margin. Something new to learn! I exposed the film in the UK summer sun at 1 ISO with an 89b filter.

 

[Maris]

I discovered that out-of-date Efke IR820 film ages in a way where the infrared sensitivity fades much more quickly than the white light sensitivity. My last batch of 8x10 Efke IR820 exposed behind a IR720 filter (fair equivalent to a 89B) had an EI = 0.17 in broad daylight. That's mighty slow!

 

[BarryWilkinson]

That would explain peoples very different EI's that they publish, thanks Maris.