How to determine if film developing chemical is still good

Some days ago I totally destroyed a 135 film developing it with a dead chemical (it was a solution of R09 done from an already opened bottle. See here). It is not a nice experience, for sure. So I started to search for a practical method to check if the developer is still good or not. This is what I found and I tested it by myself.

You can do the whole stuff in full light.

STEP #1: Put a small piece of the film on a toothpick (part of the film leader that usually you cut away before putting the film in the tank roll) and put it into the developing solution. This film has been exposed to full light so it should become totally black. Keep it in the developer for 1/5 the time you need to develope the film.

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On the left, the working developing chemical. On the right, just water.

STEP #2: wash the film under water

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Washing the film after developing it for half the time needed

STEP #3: put the film in the fixing solution and wait for 1/3 time of usual fixing time

Now, if the developing chemical is still good, you’ll get a total black film. If the developing chemical is gone, you’ll get a totally transparent film (fixing solution took away all undeveloped silver).

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Comparison between working dev solution (right) and water (left)



This is one of my two beloved film developer (the other one is the Bellini’s Hydrofen).


Yesterday I had a new experience with it, and it’s worth to be told. I developed a Fomapan 100 using a 1+50 solution from a bottle opened more or less 6 months ago.

The result was a totally blank film without anything (neither brand or frame numbers). So the developer was totally dead and, when I emptied the bottle, I found that in it there was an hard, brown crust, as if the active part of the developer became a precipitare leaving only a useless brown liquid.

Searching on the net I found another case like mine: it’s here.

So, lesson learnt: when you open a R09 bottle, after 4 months throw it away. And, in case of doubts, try to develop a small film leader to check if it is still working or not.