Tuesday, February 7, 2012

LOMAD. A Diafine clone.

After two months testing it's time to publish a Diafine clone dubbed LOMAD.
Lazy Old Man's Ascorbic Developer.

Well, you cannot be overly lazy since the second bath requires constant agitation to give good results, but when done properly you don't have to watch the clock with one eye all the time while developing. It doesn't matter if you leave the film in the first bath for 4,5 or 6 minutes. Event 9 or 10 minutes gives you the same result.
The time required in the second bath is 5 minutes, but 6,7,8 or 9 minutes will give the same result.
The temperature may be from 18c to 25c without any change in developing time.

The first bath which contains the developing agents is mixed like this:

700ml water.
15g sodium sulfite
5g sodium metabisulfite
15g sodium ascorbate
0.3g phenidone
0.1g Kbr
1g salicylic acid.
Water to 1000ml.

Sodium ascorbate is used instead of ascorbic acid to avoid the hydrolyzing step to convert ascorbic acid to ascorbate. This will make it more difficult to balance pH at 7.0.

The reason for using both sulfite and metabisulfite is to balance pH at or just below 7.0
My mix came out at pH 6.8

The second bath contains the alkali and the rest of the sulfite.

700ml water.
20g borax
100g sodium sulfite
1g KBr
Water to 1000ml.

Sample pictures:


Lucky 100 at ISO 100.



Lucky 100 at ISO 100.



Lucky 100 at ISO 100.



Shanghai GP3 at 100 ISO.

The contrast is a bit lower than normal, but for motives with high contrast that's just fine.

8 comments:

  1. With the first bath you give the developers to the film, in the second they can work in an alkali medium. Borax may be replaced by sodium carbonate or sodium hidroxide, isn't it?

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    Replies
    1. Yes in the first is
      15g sodium ascorbate
      0.3g phenidone
      which is the developing agents, in your case can be replaced by CD4 alone.....
      Borax can be replaced, this here was set for a pH around 9, to give a slowish, less contrasty development...

      Make a careful note - and I'll let out a big secret here : there's KBr - potassium bromide - in both baths! That is something I've never seen before. It was Trond's suggestion, he is the genious, and so far noone has commented upon it, nor picked it up.

      Can you think WHY we did this? :-)

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  2. Trond has published the low contrast, winter version here, snow pictures in the winter are extremely hard to get on film, and look what he has achieved! In summer one could replace this bath B with a soda-based or even lye-based....

    And there's ample room for experiments here!

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  3. All I know about KBr is that it improves differentiation between exposed and not exposed areas, reducing fog. I understand it in the second bath while developer is working. In the first bath only a little for the little activity of the developer in a adverse medium?

    ReplyDelete
    Replies
    1. It is also used as a restrainer to reduce and almost stop the total development action in the first bath. Leaving the film in the first developer for 10 minutes only results in a weak grey color on the exposed film leader. Besides that, when it is already in the emulsion when the developing action starts in the second bath, it protects better against uneven development. Infact is to the level that using a fresh second bath each time, there is almost no need for agitation. Leaving out the agitation in the second bath is nothing you should experiment with. From time to time, uneven development shows up without agatation. Constant agitation also helps the contrast up to the normal level.
      The reason for choosing borax as accelrator is that I wanted to keep the speed of development down, and thereby the grain as fine as possible.
      A side-effect of this is that you can shoot your film at approx 1 EI over box speed.
      A 50 ISO film like PolyPan-F @100 ISO works great in this developer.

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  4. Thanks for the explanation. I'll keep trying. Learning by doing and talking with others.

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  5. Good to know that about borax. I might try the recipe replacing b&w developer with cd-4.

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    Replies
    1. Good. Mix up a version with CD4 as the sole developing agent. That may give you a useable c-41 developer.

      I have to explain the borax thing a bit better. Just using borax as the accelrator (alkali) alone, doesn't give any film speed increase, but it enables me to get the contrast down to a level where I could increase the phenidone a bit, and by that get a film speed increase without getting too high contrast. This is a function of using phenidone, more than using borax.
      Another thing to remember is that when using borax as accelrator, you have to include sulfite in the developer. If you don't do that, you may get a strange shiny look of your film. Borax can do strange things.

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