I am new to LF and have been using BTZS tubes for about a year for developing my 4x5 TMax 100 negatives. I use 60 ml 1:1 diluted Xtol as this is what the BTZS cap can only hold. I agitate the tubes with a 2 cycle pinching technique. For a full 6 tube session, I pinch tubes 1+2, 3+4, 5+6, then side of water container + 1, 2+3, 4+5, 6 + side of container. This way each tube is rotated in opposite directions in a 2 cycle pinch. With this I found my EI is ASA 80 with density above Film Base + Fog of 0.11. My N developing time is 8 ˝ minutes at 75F.
Equipment involved are Toho 4x5 camera, Pentax digital spotmeter and Nikon 210W lens, all purchased new. There should be no light leaks or other failures.
Recently I got interested in stand development, adjacency effects and people’s glowing reports on 1:3 diluted Xtol. I also hoped to get some increase in film speed with this technique. The “open tubes in a can” method described by Sandy King previously would need to use a huge amount of Xtol. So I made my own tubes from grey 1.7 inch PVC piping. A 5.5 inch tube section (with cap at one end) can hold 220 ml. Just by pushing two of these tube sections together with a central connector, the tube complex is water tight. So it basically functions like a BTZS tube, except that the holding capacity is now 220 ml instead of only 60 ml in the original BTZS system. With 220 ml of fluid, the entire negative can be submerged and stand development is possible. 55 ml of Xtol diluted 1: 3 makes 220 ml, which should be adequate for 20 sq in. of film. I also found a plastic container which holds 6 of these tubes so I can agitate 6 tubes all at once by inversion.
My agitation is slow inversion and up again, taking about 2+ seconds. I invert in 4 directions. I presoak for 1.5 minutes. Then, as described by Sandy previously, I agitate a full first minute, stand for the next minute and then start the “10 seconds in 4 directions inversion agitation” every two minutes. Empirically, I developed for 12 minutes (50% increase from my 8.5 minute N development time). That took five 10 second inversion cycles besides the initial full minute agitation. I then did the usual, stop bath, fix, rinse, hypo-clear, wash, photo-flo routine.
With a new development technique I had to find my EI again. So I shot at ASA 64, 80, 100, 125 and 160 at a black board (Flocked light trap mat), placing it at Zone I. I checked the four corners as well as the centre for evenness. I also included an unexposed negative and that made 6 negatives.
And now the results:
Densities –
Unexposed sheet – 0.01
Shot at ASA 64 – 0.11 (0.10 above FB+F)
Shot at ASA 80 – 0.10
Shot at ASA 100 – 0.06
Shot at ASA 125 – 0.06
Shot at ASA 160 – 0.04
So my EI using this development technique is ASA 64, a drop in speed instead of an increase.
Even worse, the film shot at ASA 64 took on a “beaten silver” appearance, which I interpret to be uneven development. Here in my office, as far as I can recollect, the film shot at ASA 80 did not show the “beaten silver” appearance, or definitely less. The others shot at higher speeds did not show this unevenness presumably because the densities are less and so the unevenness if present was less noticeable. This did not happen when I worked with BTZS tubes.
So where did I go wrong? I thought may be my tubes are the problem. So I bought a Jobo 2521 drum together with film loading facilities and did the experiment again with 1,300 ml of 1:3 Xtol.
Densities –
Unexposed film from last year – 0.02
Shot at ASA 64 – 0.16
Shot at ASA 80 – 0.11 (0.09 above FB+F)
Shot at ASA 100 – 0.08
Shot at ASA 125 – 0.05
Shot at ASA 160 – 0.05
Again the negative shot at ASA 64 clearly showed uneven densities as “beaten silver” appearance. The other negatives looked OK, though again the lesser densities may have made unevenness less noticeable.
Can anyone help? Thanks.
Greg
www.gregoryngphotography.com
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