First Acros Develop w/ Rodinal - Shadow Grain

[Jim Cole]

I just entered into the world of B&W developing with the help of the members of this great forum. After many days of reading and research I decided my first trials of Acros 100 4x5 film would be with Rodinal 1:50 (I know of the wide ranging opinions on this developer with respect to grain). Two sheets were exposed at ISO 100 and ISO 64.

Chemical Mixing Ratios (JOBO 2500 Series tank needs 560ml):

Rodinal 1:50 - 12 ml Rodinal + 600 ml water = 612 ml
Kodak Indicator Stop Bath - 10ml solution + 625 ml water = 635 ml
Ilford Rapid Fix - 120 ml fixer + 480 ml water = 600 ml
Photo-Flo - 3 ml solution + 600 ml water = 603ml


I performed the following process at 20 degrees C and timings were done with an Omega Darkroom timer:

1) Allow tank and chem bottles to sit in water jacket for 10 minutes
2) 5 minute water presoak while on Beseler roller
3) Develop 7.25 minutes and flip Jobo 2500 tank on roller every 30 seconds
4) 1 minute Kodak Stop Bath
5) 30 second wash
6) 5 minute Ilford Rapid Fixer
7) 2 minute wash with 1 liter water (Repeat 5 times)
8) 1 minute wash with distilled water and Kodak Photo-Flo 1:200 dilution


Results

1) Subject was an X-Rite Digital ColorChecker SG card shot in daylight and almost full frame
2) As far as exposure and tonality the both negs look good with the expected differences of the ISO settings and the film used
3) I was expecting a bit of acceptable grain from the Rodinal and it looks fine in the dense area and midtones, but it is very, very ugly in the less dense areas of both negatives.

Question

Before developing new sheets, I am trying to isolate the reason for the grain issue in the shadows.

It's possible I did not mix the stop bath and fixer quite thoroughly and since I ran the fixer for the long end of Ilfords recommended time (2-5 minutes) I think it may be related to the weakly mixed and too long time of the fixer, rather than any developer issue, but since I am a newbie I don't have a clue. Of course it may be over agitation, but I doubt it with so many using the Unicolor or Beseler powered rollers.

Could anyone shed a little light on this grain in the shadows issue?

Thanks,
Jim
www.jimcolephoto.com

Edit: I added a cropped section of the scanned and inverted image.