Below is some BTZS data derived from testing Fuji Across, 120 size, in Pyrocat-HD with what I call extreme minimal agitation.
For those not familiar with Fuji Acros it is a very fine grain, very high resolution medium speed film, of ASA 100. When used with a high quality medium format 6X7 or 6X9 camera and lens, and exposed on a tripod, this combination is capable of results equal to, or in some cases superior, to 4X5 LF when using higher speed films.
The Pyrocat-HD dilution was 1:1:100, with development at 70F. The film was agitated vigorously for one one minute at the beginning of development, then for ten seconds at the one-quarter, one-half and three-quarter points of development. No pre-soak was used. The stop was 1/2 strength acetic acid, fixer was Formulary TF-4.
When the step wedge negatives were processed and dried they were read with a densitometer (Blue Mode) and the curves were plotted with WinPlotter. The EF (exposure scale) in WinPlotter was set to 1.40, which should give good results with VC silver gelatin papers. For scanning I would recommend reducing development times by about 15%.
Results below.
SBR Time
9 11 minutes
10 14 minutes
11 20 minutes
12 29 minutes
TIME Average Gradient (Approximate CI)
10 0.5
12 0.55
14 0.60
16 0.65
20 0.70
24 0.75
26 0.80
30 0.85
The tests indicate that the EFS (effective film speed) of Acros is about 115 with this developer and type of agitation, and is virtually the same from SBR 9 through SBR 6 so no change of development is indicated for Plus or Minus develoment within these limits.
Sandy King
For those not familiar with Fuji Acros it is a very fine grain, very high resolution medium speed film, of ASA 100. When used with a high quality medium format 6X7 or 6X9 camera and lens, and exposed on a tripod, this combination is capable of results equal to, or in some cases superior, to 4X5 LF when using higher speed films.
The Pyrocat-HD dilution was 1:1:100, with development at 70F. The film was agitated vigorously for one one minute at the beginning of development, then for ten seconds at the one-quarter, one-half and three-quarter points of development. No pre-soak was used. The stop was 1/2 strength acetic acid, fixer was Formulary TF-4.
When the step wedge negatives were processed and dried they were read with a densitometer (Blue Mode) and the curves were plotted with WinPlotter. The EF (exposure scale) in WinPlotter was set to 1.40, which should give good results with VC silver gelatin papers. For scanning I would recommend reducing development times by about 15%.
Results below.
SBR Time
9 11 minutes
10 14 minutes
11 20 minutes
12 29 minutes
TIME Average Gradient (Approximate CI)
10 0.5
12 0.55
14 0.60
16 0.65
20 0.70
24 0.75
26 0.80
30 0.85
The tests indicate that the EFS (effective film speed) of Acros is about 115 with this developer and type of agitation, and is virtually the same from SBR 9 through SBR 6 so no change of development is indicated for Plus or Minus develoment within these limits.
Sandy King
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