Ran a few tests with TXP--the first time I've tried FX6a with a modern hardened emulsion--and got a really good result by the third sheet. Contrast is a little high, but I think I can fix that by being a little more careful about temperature--I was at 74 degrees F and should really be at 68 F, since there is no way to adjust for temperature without changing the chemistry. Grain looks normal, and speed is easily EI 320 with a little room to spare. The emulsion also came through the process cleaner than Adox PL100 or Fortepan 400.
Details: 4x5" Tech V, 150/4.5 Xenar, f:12.5, 1/250 sec., 3x yellow filter, FX6a with 105g hypo/l, 6 min. Detail--full res neg scan at 1000 dpi.
there' a little info on monobath dev at Barry Thorntons old site at the "bleach monobath" page. It includes a formula or two.
That's interesting. He uses it in a bleach and redevelopment process for reducing contrast.
It's a bit like a proportional reducer, I thought the idea was interesting.
I've been testing a camera that just came back from the repair shop and using my FX6a monobath with 105g/l hypo to process the test rolls, so I have a couple of new observations.
1. The temperature is really critical. I made a point of tempering the solution to 68-deg F this time, and that solved the high contrast issues with Adox 100 (EI 100). The upside of this would be that I could use temperature to control contrast, as long as I have to temper the solution anyway. According to Haist, the theory behind this is that rate of development is more temperature sensitive than the rate of fixation.
2. I tried (old) TX 400 and got a good EI 400 and normal contrast out of it, so that's another film that works.
3. The sludge left an unpleasant film on the Tri-X, so I guess it's time to replace the solution, and maybe I should decant and filter between development batches. Meanwhile, I just wiped it off with a wet soft paper towel, put the film back on the reel, and continued to wash it, and it seems fine.
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Any sign that the film on the Tri-X was really dichroic fog? Sometimes monobaths do this. There are ways to prevent it.
It was kind of silvery blue and wiped off easily. It seemed more concentrated in the thin parts of the negative. When I've gotten dichroic fog it's been more pinkish. Any ideas?
Probably sludge, but Monobath developers are known to form dichroic fog. The silver complexes are hard to keep in solution and eventually they begin to turn into silver metal. This can 'plate out' on film or settle as fine sludge.
Modern films from Kodak, Ilford and Fuji are rather resistant to dichroic fog IIRC.
I posted an image of a print from a TX/FX6a neg on Efke Emaks G2 in the gallery. I've got the new darkroom light tight enough to print and process film at night. A little more work to do before I can work during the day.--
The digital image is kind of noisy, but the print has very nice gradation and a crisp look.
I've started experimenting with monobaths.
I decided to use Donald Qualls' formula, simply because the ingredients were easily available - or so I thought.
Jessops don't stock HC-110, and other places would have been closed by the time I could have got there.
Undeterred however, I grabbed a copy of Ilford's competitor equivalents datasheet and saw that as equivalents for HC-110 they list Ilfotec HC and LC29.
I have a bottle of LC29, so I decided to experiment with that and FP4+.
The first experiment was a resounding failure. I used the quantities listed in DQ's formula, and got very slight development and no fixing, even after around 30 minutes.
For the second try, I modified the formula after looking at the tables on the dev bottle.
I made up 200ml, using 20ml each of dev and fixer, along with 30ml 9.5% ammonia solution.
To my surprise and gratification, it worked!
The negs are quite thin, and have a line running across them, as I didn't mix up enough to completely cover the film, but for all that, they are completely cleared, and there is an image there - probably printable in most cases.
I now need to tweak the formula to give better development, so I'll post again when I've got more results.
In true fast process style, I dropped the negs in isopropyl alcohol to dry them quickly, and I've just scanned one, attached.
Please excuse the dust and other garbage on the scan.
Pentax Espio 115G, Ilford FP4+, straight scan from neg
Last edited by ben-s; 08-30-2008 at 09:15 PM. Click to view previous post history.
Reason: added info and image
Lens caps and cable releases can become invisible at will. :D