ARS-Imago Monobath MB Developer: Initial Thoughts – By Steven Bleistein

It is rare for me to come across a monochrome film developing chemistry that I have not seen or heard of before, particularly in Japan. So when I noticed Swiss company ARS-Imago’s relatively recently released Monobath MB chemistry on the shelf at Yodobashi Camera in Akihabara, Tokyo, I thought I might give it a go.

Kodak Tri-X 400, Pushed to 800

Monobath developers have always intrigued me, if for nothing else, cutting out a step in the development workflow. Cinestill has a monochrome monobath developer, but I have never found it available in Japan, and it is not important enough to me to order it from overseas and have it shipped. But here I was in Yodobashi Camera, with ARS-Imago product sitting in from of me on the shelf, whispering to me, “Buy me. I dare you!” So I did. 

Kodak Tri-X 400, Pushed to 800

ARS-Imago Monobath MB is not exactly a bargain. At ¥5390 it is not quite twice its 23 euro cost in Europe, but a significant step up. According to the ARS-Imago’s data sheet, you can develop about fifteen roles of film for that, reusing the one-liter of solution, or you can dilute with water to make two liters of one-shot. Assuming you need about 300ml of solution to develop one role of film, that’s about eighteen or nineteen rolls at the outside. As for cost per roll—well, you can do the math. Only one caveat—use up the solution within two months, because it does go off.

Kodak Tri-X 400, Pushed to 800

By comparison, for ¥2600 I can make five liters of Kodak T-Max developer, from which I can develop at least fifteen rolls and maybe sixteen, without reusing. Of course, I still need to factor in fixer cost, but even so, the cost per roll with T-Max Developer is just about half. Now if I use D-76, I can reduce that again by two-thirds. 

Kodak Tri-X 400, Box Speed

In any case, it is not really about the money. It’s about the ease of workflow and the quality of results. As for workflow, it is pretty straightforward. One bath, at 20~24C for eight minutes, agitating for the first half-minute and then inverting twice every thirty seconds. Wash. Add wetting agent, and Bob’s your uncle!

Kodak Tri-X 400, Box Speed

The 20~24C temperature range is nice, as that is pretty much room temperature most of the year for most people, and you have a lot of wiggle room. Not particularly onerous. As for mixing, for the reusable solution of one liter, just mix the contents of bottles A and B, one-to-one. No need for a Ph, D. In chemistry. For the one-shot solution, just add another liter of water, which makes for some added complexity, but I think I could manage that in a pinch.

Kodak Tri-X 400, Box Speed

Now something about this developer. ARS Imago does not recommend using it on T-grain films and suggests you get some pretty nasty results if you do. I did not try that out for myself. I’ll just take their word on it for now. So that means forget about using the monobath on any of the Kodak T-Max films, Ilford Delta, or Fujifilm’s Neopan Acros variations. As for cubic-grain films like lford Hp5 and Fp4, Kodak Tri-X, Rollei RPX, Fomapan or Kentmere—well, knock yourself out!

Kodak Tri-X 400, Pushed to 800

So that’s what I did. The photos in this piece, I shot with Kodak Tri-X 400. I shot some photos at box speed and others pushing one stop, which I increased the developing time to eleven minutes rather than the standard eight as a guess. I used a Leica M3 with first-gen Summicron 35mm f/2, and a Y2 yellow filter.

Kodak Tri-X 400, Box Speed

Judge the results for yourself. In my opinion, ARS-Imago Monobath MB is a fine developer, with nice, contrasty results, and an easy-peasy workflow. If that is worth it to you, the cost makes sense.

Kodak Tri-X 400, Box Speed

I am a street photographer who lives in Japan. If you would like to see more of my work, have a look at my website, or my Instagram @sbleistein

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12 thoughts on “ARS-Imago Monobath MB Developer: Initial Thoughts – By Steven Bleistein”

  1. I”m getting great results with CineStill’s DF96 monobath, which is available in powdered form or liquid. I warm the solution to 80 degrees F, which allows me to process a roll of film in about 3 minutes, plus a brief wash and a dip in wetting agent. Quick and easy!

  2. Hi Steven, some nice results with the shots published here…

    I could have sworn that ARS Imago was Italian though?

    I remember standing outside their shop in Rome at Christmas 2018 (28th December) waiting for them to open, so that I could buy precisely this product. Of course, they were enjoying a break, which did not include opening at all until the new year was “in”. 🙁

    They are also responsible for the Lab-Box daylight developing tank, which finally made it to market late last year.

  3. Thanks for this Steven – looks great. And perfect timing, as my daughter asked just yesterday if I would show her how to develop films! Having not touched a tank for over 20 yrs myself I was feeling uncertain, so it was great to get your insight. I’ll see what I can get hold of, and away we go! Cheers.

  4. Steven – Based on your [granted] limited tests, do you prefer your results to stand developing in dilute Rodinal?

  5. I’m intrigued that a longer time increases development, when at some point the chemistry must shift itself from Develop to Fix. That implies it somehow ‘knows’ that you’re pushing the film.

    Df96 uses temperature to vary development, which intuitively makes more sense to me, in that it shifts the rate of reaction and the crossover point when fixing takes over. The other night I talked the Df96 mechanism over with my son, whose Chemistry A-level is 30 years more recent (and two grades higher!) than mine. I’ll try him again on this one.

  6. I like your results Steven. It encouraged me to try a monobath developer too. Since my fav film is a Tmax 400, I’ll give the Cinestill monobath a try.
    Hope to see more results!

  7. Good to read this review, as I’ve submitted a review of the Cinestill Df96 to 35mmc, and hopefully that will be online soon. I must say I enjoy working with a monobath – it’s all so easy. Now we have the Ars-Imago as well, and your results look good.

    1. Not sure what you mean by “pushing in camera.” The Leica M3 is a completely manual mechanical camera. I used a light meter, measuring for ISO 800 rather than 400. Pushing is something you do in processing. In camera, you underexpose.

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