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Sunday, March 31, 2013

Superadditivity between Caffenol and CD4

The process C41 (color negative) uses as developer agent a derivative of p-phenilenediamine called just CD4 because its chemical name is terrible. If you wish to know, just search in internet, but I don't think it is of interest now. When I develop color today, I prefer the 2-bath developer of Dignan, whose formula is given here.

I made 1 L of bath A and I still have more than 3/4 liter after developing several C41 films, I even don't n know how many...

CD4 is also a B&W developer. I was trying to use it as such and I made a bath B of Sodium Sulfite and Carbonate with a pH of about 11 or maybe a little above, wheeling to test CD4 as B&W developer. But I didn't use it in a split mode, I joined instead 10ml of bath A to the bath B and putted a strip of film in it. Waited and waited and nothing happened. Because I already tested Caffenol strong with this B solution and it took some 30 minutes or more to develop, I thought that maybe a small amount of Caffenol Strong would bring help. Yes, it did! Only 1% of Caffenol boosted the developer to develop in just 5 to 10 minutes.

CD4 + Caffenol Strong
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Note: I have been testing this new Caffenol that maybe called Super Strong. A first formula for the concentrate solution can be this one:

700 ml water
5 g Sodium Sulfite
100 g coffee
100 g Vit. C
6 g CD4
Water to make 1 L

1 liter is too much, it will last forever. I would rather make just 100 ml or maybe 250ml.

For the basic bath I suggest:

700 ml water
60 g Sodium Sulfite
20 g Sodium Carbonate
1 g Potassium Bromide
Water to make 1 L

Usage:

Use 1% of Caffenol Super Strong (CSS) in the basic bath.

Developing time at about 18ºC was measured to be cerca 10 minutes with Fomapan 400.

I didn't use this recipe yet with a roll film, only with stripes of film. I hope to do this tomorrow, I can't wait for the results, I am very optimistic about quality.

Another note: Times depend very much on pH and Potassium Bromide quantity. For the last I have 250ml of a 10% solution and I measure it very accurate with a siringe. 1g are 10ml of this solution per liter of basic solution.

New achievements (2-4-13):

The basic bath I suggested has too much sulfite and when the development is longer it will dissolve the silver and undesired deposits may occur on film. So, I made followuing adjustments with better results:

700 ml water
20 g Sodium Sulfite
20 g Sodium Carbonate
1 g Potassium Bromide
Water to make 1 liter

Use 2% of the Caffenol Super Strong instead of 1%. Development time is about 10-20 minutes at 20ºC.

New actualization (2-4-13 again):

I have just developed a roll with the basic bath as above mentioned + 2% of Caffenol Strong 30 minutes at 18ºC, just in case... Sometimes the tests with stripes are not confident and better overdeveloped than under. Looks OK, so far. In some hours I will post the photos. The shutter of my new made camera was giving double exposure (see the upper part of the picture of this post), I think this has been fixed now.

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