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Wednesday, February 27, 2013

Caffenol Strong, new findings

Some days ago I developed a 120 B&W film in the recipe that I called Caffenol Strong. If you are following this blog, please see 2 posts earlier. I forgot adding KBr (potassium bromide) and the result was a very dense and foggy negative. Some of the photos could still be saved, like the following:

Old windmill
The color is the inverse of the negative blueish color, maybe automatically tonned by scanner or software. The fact is that this Caffenol gives, with Fomapan film, a «sepia» or, if you wish, a coffee stained positive image.

The amount of KBr is crucial for both avoiding fog and accutance of the photos. Also the developing time is considerably influenced by this amount. I have been using 1 g/liter of KBr but today I decided to use just 0,5g/liter to have a decent development time of less than one hour.

I am still waiting for the film to be fixed with common salt (sodium chloride) because the ammonium thiosulfate is producing strange white spots (black in negative). Salt fixing takes a long time, some hours depending on temperature and concentration. The film is now clear after 3 hours but needs 3 hours more to be considered fixed. I hope I can show the results of Caffenol Strong + Salt in the next post.

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