Wednesday, March 6, 2013

Will you try Caffenol Strong?

I would like to engage more people with this developer that uses very little amounts of coffee and Vit. C and that you may store almost for ever, although in stock solution. I know nothing about reusing the work solution, never tryied. I prefer to use a fresh prepared work solution and this is what a hobby photographer should always do because the number of films is small, most of the times and you may want to use other developers and not only of one kind.

I repeat here the recipe of the stock solution of Caffenol Strong for 100ml:

20g soluble coffee
20g Vit. C
0,5g Sodium Sulfite or other preservative like metabisulfites


Boil half a liter water for some minutes and let it cool. Dissolve 0,5g Sodium Sulfite in this water (not easy but you may have a stock solution (with boiled water) of, say, 5g NaSO3 in 1 liter, and use about 100ml of this solution.

Assuming this, take some 50ml of this solution and add the coffee and vit C, let the foam settle and complete with the sodium sulfite water to make 100ml. Store in an amber bottle.

In the curve above, the times I got for the B&W film Fomapan 100.

To make the work solution:

Dissolve 25g of Sodium Carbonate, aka Washing Soda, and 0,5g of KBr in 500ml water and add 5ml of the stock solution to it. Use this as developer.

If you don't want or if you have doubts about this, I may send you a 50ml bottle of the stock solution for you to try. Using 5ml per film this will develop some 10 or more films. This offer is for the first 5 interested commenters.

One of the last films
It has been difficult to establish the times due to the weakness of the developer, very sensible to the variations of KBr wich is a restrainer but also cares about less fog and accutance of the photos. The photo above is underdeveloped, I had 14ºC temperature tap water and gave only 90 minutes instead of maybe 120 minutes.

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