Film developer dilutions for control - & tap/distilled water & graingreenspun.com : LUSENET : Large format photography : One Thread
Anyone else out there worked with Xtol at various dilutions for your plus and minus developing control? I find better results by changing dilution rather than just more or less time. Any pitfalls I am not aware of that may come up, or some subtle changes in the contrast, grain, separation, etc. that I might see as I move on? Second, in the 91 Photo Techniques there is mention that John Sexton came up with more grain and less sharpness in negatives when developing using distilled water for chemistry than using tap water. Anyone have more info on this one? Thanks in advance for any comments, especially if you have done any testing on these.
-- Dan Smith (firstname.lastname@example.org), March 18, 2000
I use a similar system with HC110, using dilution rather than time. Works fine. I've seen some testing done by Phil Davies on this issue. He basically concluded that as long as the necessary time adjustments were made, there was no problem. He tested XTOL also, if I remember right. All the film curves looked quite normal, no funny kinks or bumps. I think there are some advantages to this system. It helps you avoid uncomfortably short development times, especially with extreme contractions. It gives very even development since you're able to use longer times. It is especially useful if you use a rotary style continuous agitation method like BTS tubes, JOBO etc. The continuous agitation often provokes runaway highlight densities. I get much better results by diluting further and adjsuting times. For e.g., I see recommendations of about 8 mins for FP4 in HC110 1:7 from stock. I would get quite a bit of overdevelopment. Adjusting times downward helped to get an OK density range but contrast still seemed problematic with higher contrast in the highlights and lower contrast in the shadows, sort of like a long toe film (which would seem to make sense theoretically). A 1:9 dilution from stock yielded a much more even contrast and gradation. I'm sure there are also individual developer idiosyncracies worth exploring. I think there's many things dilution affects, which probably should affect micro characteristics. First, it lowers the ph of your developer. Second, it makes it softer. For e.g., D76 undiluted is a solvent developer which should give you fine grain. Diluted at 1:1 drops the solvency effect and you get somewhat larger grain. However, with larger formats, grain is seldom an issue (especially for me since I seldom enlarge to beyond 8x10 or 11x14). I think film defines the ballpark as far as grain goes i.e., a 50 speed film in a non-solvent developer will still be more fine grained than a 200 speed film in a solvent developer, which means unless you're making huge enlargements, its less of an issue from a developer choice perspective. However, XTOL is a solvent developer and its worth checking for these effects dilution could have. DJ
-- N Dhananjay (email@example.com), March 18, 2000.
Another variable would be the agitation method. There is a good discussion of dilution effects in Anchell & Troop, Film Development Cookbook. They don't address your control methodology question directly (if I remember correctly), but you can extrapolate a lot from what they do say. On the second point, maybe the better question is as to what was dissolved in John Sexton's tapwater.
-- Ian Binnie (firstname.lastname@example.org), March 24, 2000.