Two rolls of Acros-100 developed in XTOL and the concentrate look identical. The details are below. My testing so far shows that the concentrate behaves like XTOL for Kodak, Ilford and Fuji emulsions; for T-grain and traditional grain; and for 100- and 400-speed.
The concentrate had been kept in the refrigerator for a week, in case anyone cares. Here's a graph from a Stouffer wedge on my light-table, showing the density-curves for XTOL and the concentrate:
And here are full-resolution (2900 dpi) crops of neg-scans of the same frame-numbers from each of the two rolls:
Frame 24: Xtol: acros-xtol-crop24.jpg Concen: acros-conc-crop24.jpg
Frame 25: Xtol: acros-xtol-crop25.jpg Concen: acros-conc-crop25.jpg
Frame 26: Xtol: acros-xtol-crop26.jpg Concen: acros-conc-crop26.jpg
The curves, grain and sharpness are all essentially identical to my eye.
@Rudeofus: Ryuji said that APX-100 and Pan-F worked poorly in DS-10. Pan-F is still in production, so I'll order some rolls and try it. Thanks for posting that idea. BTW, I thought Ryuji speculated that the failures were caused by DS-10's low pH of 8.0. I'm running at 8.3, which is a tad above XTOL and the same as D-76, so at least the concentrate won't have problems due to low pH. Nonetheless, I'm going to test Pan-F.
What problems do dissolved minerals in water cause? A search of apug.org shows some calcium specks on negatives if it precipitated out of solution. Also, folks say that carbonate causes calcium to precipitate, which my concentrate lacks, so hopefully that won't be a problem. My tap water is hard, so I'll try it on test-strips tomorrow.
One problem with sequestrants is that many are inorganic salts, and thus won't dissolve in PG. Citric acid is an exception, but it's a rather strong acid that I'd need to compensate for somehow.
@choppastyle: From a cost point of view, a low-volume shooter will save a little money using the concentrate. But my main motivations are (1) I hate to discard litres of expired developer every 6 months, (2) after 4 months, I lose confidence in XTOL and wonder if sudden death will hit me, and the concentrate will give me confidence for much longer, and (3) a little sulfite precipitates out of Xtol's solution, which looks like shredded tissue floating in it, and a poster said those are "hot" and can cause overdeveloped spots on negs. I've had that shredded tissue issue in both of my batches of Xtol, and solved it by vigorously shaking the bottle when warmed. The concentrate won't have that problem as it's mixed shortly before use.
I'll do more tests, but the big test now will be longevity, and that takes time.
EDIT: For the Acros rolls: Xtol leader density was 3.09, and concentrate leader was 3.10.
Last edited by albada; 07-21-2012 at 12:48 AM. Click to view previous post history.