Film Testing (WBM) Curves 320TXP in XTol 1:1 Too Contrasty—How Did I Mess Up?
I have just completed my first, Way Beyond Monochrome 2, film test, this morning. Since I have not used 320TXP (4x5) for a while (normally HP5+) I decided to test it, in my usual developer, XTol 1:1 20˚C. I use CombiPlan, with fairly intensive agitation: constant during first 30s (~15 full inversions), then 5 rapid full inversions taking a total of 6 seconds, every 30s, with a triple-rap-tap to dislodge bubbles. Incidentally, my sheets stay put, they never slip out with 320TXP, HP5+, or FP4 (I would get a rare slip with TMax 100). I did 5 sheets at a time.
Looking at the resulting curves (see the attached Excel spreadsheet), it seems I am getting too much contrast right from the beginning, even with short development times, eg. average gradient 0.59 at 4 min, and 0.92 at 16 min! It seems I cannot get N, not to mention N-1 this way... Clearly, I have done something wrong while testing.
I have a few suspects for the cause, and I wonder if those of you who have done this before, or who have other film testing experience, would be kind to suggest a clue and a fix, as I will re-run the test again in a while:
- I think I have underexposed the whole thing by 1.5+ stops. WBM suggests metering at box speed, so I used ISO 320. After calculating the bellows factor (1.5 stops in this case), I was running against long exposure reciprocity (Irish summertime), and I went ahead with an uncorrected 1 s exposure at f/9, while I should have used a longer time. Further, my Nikkor runs 1 s as ~0.9 s. Can I blame my underexposing?
- As I asked on another thread I was not sure how to photograph my Stouffer 31-step 4x5 transmission tablet. It was recommended to me that I should stick it to a window, as the test needed daylight (I photograph landscapes). That is what I did, but using 300mm Nikkor, with even a 52cm extension, all I managed to get is about a 70% reproduction, so the tablet on my negs is smaller than the real thing. I wonder if its overall density could get "squished" because of the smaller reproduction. Does the test require repro at 100% scale? If so, I am not sure how to do that with my field camera (Ebony SV45Te).
- Through the window, I could clearly see distant objects (10-50m away). I placed a sheet of milky perspex about 8m away, angled towards the cloudy sky, outside in the garden, so I had a more even illumination behind the tablet. Even with the background well out of focus, I suspect there was a different illumination between the upper (1-16) and lower (16-32) tablet bars, as the tops of the bars 1-16 have less density than the bottoms of those bars on my 25 developed sheets (bars 16-31 are quite even). I collected the data consistently in the same spot, as close to the centre as possible, using a Heiland TRD-2. If this is the reason, then the through-the-window technique not going to work for me.
- I worked fast, but this is Ireland, and the weather, cloudy with our normal drizzle, could have been slightly changing the lighting. I tried to compensate by shooting 5 sheets for each development time, and I have averaged readings within each development time series of 5 sheets, but I could not compensate for a gradual change in lighting across all the series. With hindsight, I should have grouped the sheets differently.
- This box, like most of my film, has been through at least 2 airport hand-luggage x-rays, mandatory in Ireland and UK (no hand inspection allowed), but I doubt this would have other than the same overall effect.
- I am agitating too much for those development times.
I am off to photograph in Wyoming for two weeks, tomorrow. I will use my 320TXP, and I plan to use the rule-of-thumb-rating of EI 200 for N, 250 for N+1 and 160 for N-1—suggestions? When I am back, I will run another test, hopefully helping me figure out the best dev times.
Please help me make the best choice, and thank you, for sharing your experience, for which I am always grateful.