Here is the link that the excerpt below, comes from
I have highlighted an interesting comment which needs to be tested.
And Bravo to Donald!
Donald Qualls , Feb 29, 2004; 08:18 p.m.
Monobath from commercial chemicals: success!!
"Second results:
400TX 135, souped ten minutes, 75 F.
16 ml HC-110 USA concentrate
50 ml household ammonia (ammonium hydroxide, probably 5% solution)
10 ml Ilford Rapid Fixer concentrate
water to make 256 ml
Mixed by adding most of the water to the HC-110 concentrate, then ammonia, then fixer, then remainder of water to make up volume. Heated to 75 F in an external hot water bath.
Result: normal appearing negatives, within approximately 1 stop of rated speed at worst. I won't know for certain until I can scan them (they're drying now, probably won't get them scanned tonight), but to my eye contrast range appears normal and low light details are preserved -- I intentionally shot at a wide range of exposure, from about +2 to -2 stops, to test whether the latitude of the 400TX would be preserved, and it appears it was; there is considerable detail in a shot taken with a simple camera (most likely f/11, 1/100) in a grocery store aisle by available light, a situation that normally demands f/2.8 at 1/30 with ISO 400, give or take one stop.
Worthy of note that the concentrates used have excellent keeping properties, and household ammonia is a common cleaning supply available worldwide. Even accounting for use of distilled water both for mixing and a multi-change stand wash, total cost per film is about $1.25; if tap water can be used for wash, cost is more like sixty-five cents per film in 35 mm -- 120 would be about double this, since twice the solution is required for the same film area (unless one masters back-to-back loading). Film processed this way should be archivally stable if properly washed; even at this 1:24 dilution, the fixer has about 200% capacity over that needed to fix 80 square inches of film per above batch of monobath.
I'm pretty happy with this, as you can probably tell."
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11 comments:
The sq/ft of a 36 exp 35mm roll is the same as a 120 roll, yes? I don't think you need more chemicals for 120.
Wait til you see how little I try to use on one piece of sheet film.
I got incomplete clearing (at first appeared to be chemical fog, but not) with this formula on Ilford Pan and Tmax, but it does produce a fairly normal negative with a long toe. This is in a bath situation. I will try it on some tri x if I can find it here.
Another try with the same Ilford emulsion and the same mix, but at a little lower temperature, resulted in a much thinner negative with little detail in the shadows. But we will scan them in and see what we can see.
Poor clearing may be a result of differences in the film grain formula; T-grain films (TMax, Delta, Foma Creative 200) are infamous for requiring more fixing than conventional cubic grain types (Tri-X, Plus-X, etc.). Not sure about the Ilford Pan, and it's been several years since I did this experiment (I don't normally need a monobath). Try leaving the film in the soup longer, maybe 20 minutes instead of 10, or increase the amount of fixer by 50% for T-grain type films.
Reducing temperature affects development rate more than fixing rate, so you'd expect to get reduced density -- 75º F isn't hard to get to, and it's not very critical, but 68º F will lose film speed for sure.
Donald, thanks for the comments. We've found that your monobath works in 2 minutes on Efke 25 and certainly under 6 minutes on PanF, but that TMX takes longer, but we get excellent results IF we keep the pH at 9.5. That seems to be a key aspect and is easily measured with pH test strips that are cheap and quick. To get the clearing effect we were after, it was necessary to use fresh monobath (we had used some at least three times and it got fairly muddy and there was a lot of pecipitated silver.
What we were not expecting was the quality - if you look elsewhere on the blog you will see Efke results are sharp and grain free. Even the two minute thick reagent (your concoction plus methyl cellulose) did a good job on the very thin Efke in two minutes at room temp, but with less contrast. That led us to think this was (and we still do) the answer to an alternative gel reagent such as Old Pol used to use.
Thanks!
Bob
I've been using this for two years now. Nothing is easier. The trick though is to process at 75 degrees or even a little warmer. Once mixed, it lasts for a long time, months at least.
Bob thanky you very much for the information, i would like to test the monobath on one efke 25 sheet, can you tell me how much solution i would need to test process one sheet 4x5 efke25
greetings
you only need a small amount, but what would be the point of doing just one once you got set up? Mix it up according to the above. Process with the solution warm. Any black and white film can be processed in this mix.
Thank you Bob, i wanted to test the solution in order to do 10 sheets at once,
got a jobo 3010 expert tank, that i would like to use with rotating agitation
so Efke25 4x5 , 2 minutes is a good starting point?
You don't need to agitate after the first agitation by hand is done. It's a monobath and like polaroids no agitation is needed once wetting is accomplished, but you can if you want - streaking is likely with lots of agitation. Just start with 75-80f and you will be fine. 2 minutes is fine. If you need more clearing, take a look and leave it in a little longer.
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