Summary of findings, about analogue film development:
1. caffenol.blogspot.com/ is a great place to start for homebrew developing.
2a. Longer development times (more than 8 or 9 minutes) allows a slower stopbath; e.g. pure water – just wash for 30 seconds or until what comes out of the tank is water (that is about 90 seconds for my caffenol developer).
2b. Shorter development time, or wish for more precise and faster stopping of development: 5-20g citric acid per liter water makes a well-working stopbath, consider 15g/l “normal”.
2c. One more alternative to stop: http://en.wikipedia.org/wiki/Stop_bath – acetic acid at 1-2%
3. fix appears harder to replace with homebrew. (note: pH plus and pH minus for pools are candidates!)
Take a piece of film (the leader!) you’re about to fix, place e drop of fix in the middle of it – leave it for 1-2 minutes. Then put the entire piece in the fix – this allows to check against the middle drop-inflicted as clears. If it clears in two minutes or so; double the time and fixate your film at least that long. If the leader doesn’t clear in three minutes, consider the fix near its life time – preferably make a new working solution.
citric stop –
en.wikipedia.org/wiki/Bromothymol_blue is what is used in indicating stopbaths, just need to know which pH to look for.
General thumb rule for unknown combination of film and developer,
… in daylight:
1. Cut off a piece of the film,
2. Pour up/mix working solution of developer,
3. Use e.g. a toothpick and place a DROP or two of developer onto the film piece. Spread it out as a good sized dot on the piece of film piece
4. Wait until you see the film darkening under the drop-spot, say 4-5 minutes..
5. Start a timer and put the entire piece in the developer
6. Wait until you cannot say there is DIFFERENCE between the drop created spot and the remainder of the piece w.r.t blackness
7. STOP the timer.
8. Put the piece in fix and let it fixate properly, this will help in judging the result: If there still is difference, add to/elongate the development time you pick (below).
The reading on the timing device is 1/4 to 1/3 of an initial development time to try.
(Muliply the reading by 3 and by 4 – try something in that interval)
The time it takes for the entire film piece to be completely uniform in color gives you a clue to how long you need to develop your film.
To get further, shoot a film and develop accordingly, adjust towards longer time for more contrast / more grain / darker negs.
If there is no darkening happening in step 4 – reconsider / check the dilution or developer freshness.
This is started as a slightly modified version of this:
a) spill a few drops of developer on your fingers, it usually isn’t neutral pH – which means it will feel “soapy”,
b) put your fingers in the stop bath, the soapy feeling should disappear quickly.
c) Wash your fingers before you rub your eyes, poke nose or similar.
Stop bath alternatives (as said above)
Pure water works well if your developing time is 8-9 minutes or longer, wash for 30 seconds or more (Caffenol may require 90s).
A regular Acetic Acid stop bath is 2%, some say 1-2% is OK (diluted from the Acetic Acid / white vinegar you use in your kitchen)
A regular Citric Acid stop is 1,5% (15g/l), others say 5-20g (E330). A commercial stop may contain “indicator” which changes the bath color from Yellow to Blue around a pH of 5,5
Apart from a more precise developing time a stop hardens the film a bit. And it gives your fixer a longer life span due to less cross contamination of the developer in your fixer.
edit: 2012-06-02, wording, order of paragraphs and developer test review (which was wrong!)
edit 2013-09-21, expanded on the fix and developer tests – place a drop in the middle first.
edit 2014-05-24, moved developer test here from below