Does continuous agitation need less chemistry than intermittent manual agitation?
With intermittent manual agitation, my tank is full with chemistry (550ml) for 2 rolls of 135.
I'm assuming this is because of the still periods where the tank will be upright and it has to cover both reels.
However while in continuous rotary agitation, since the tank is horizontal and is constantly in motion, I am assuming it would require less chemistry.
Can someone confirm this hypothesis? Someone who has used both methods?
Firstly, welcome to the world of colour developing.
The real answer to your question is: it doesn't matter whether you use rotary developing or inversion for developing, the capacity of the chemistry is the same. I have developed thousands of C41 colour 135 rolls of film with rotary processing. I have also developed hundreds of rolls of C41 colour film using the same tanks but using inversion processing.
Essentially, the capacity of C41 chemistry is 8 rolls of 36 exposure C41 film per litre of chemistry. So your Unicolor 1 litre kit should be capable of processing 8 rolls of C41 36 exposure film very well. It is possible to develop more films, but degradation does set in, not to an alarming degree, but the more film you put through you will eventually see possible issues as you process more and more rolls.
I would suggest you make a very simple roller base so you can hand rotate your Jessops tank in a container filled with warmed water. Something like this would work perfectly well.
https://www.google.com/search?q=job...80#imgrc=g0-SgY_sMpSttM&imgdii=WM2CL83gdnhgeM
I don't know much about the Jessops tank, but from what I can see online and from your description of the volume you need, things should work out quite well. My main way of developing C41 36 exposure film was to use rotary processing in a Jobo 1540 tank, which holds 4 rolls of 36 exposure film and requires 500ml of solution. With this process I use a one shot developing system and develop 8 rolls of film using 1 litre of chemistry.
I am guessing with your Jessop tank, you could use 250ml of solution by rotary processing and develop two rolls of film at a time. This would mean you will realise the correct capacity of your chemistry for the first 8 rolls with the best possible developing outcome. After you have processed 8 rolls in the 1 litre, you could try developing 1 roll of film at a time using 250ml of used solution per roll. I think by using this method you will have another 4 rolls of film that should have pretty good quality. After 12 rolls of film I don't know as I've never done that, but I have done 12 rolls a few times around 30 years ago.
I would suggest you use simple glass jars, old jam jars or other foodstuff jars with a plastic coated underside lid will be very good and very cheap. Store new and used chemistry in jars like this and use glass marbles to eliminate air as much as possible. I have used this technique of glass jars and glass marbles (the same marbles) for over 40 years for both B&W and colour developing chemistry with great success.
Your Blix, which is a combination of Bleach and Fixing chemistry solutions, will have close to double the capacity of your developer, that is the good news. The bad news is that these are two different steps of film development chemistry and work against each other, so over time the solution becomes unusable. I looked at the Unicolor C41 instruction sheet, it is pretty good and their suggestions of over capacity seem right to me.
I would suggest you do the stabiliser bath, which is the very last bath, outside of the tank with the film off of the reels. I myself use a 500ml stabiliser bath in a 1 litre plastic kitchen jug. I take the film reel out of the tank, then pull the reel apart and drop the film on it's edge into the stabiliser for around 30-60 seconds. I then take the film out and hold it at an angle until the majority of liquid has drained from the film. I then place the film somewhere to dry. Do not rinse the film after the stabiliser bath, nothing should be done from the stabiliser bath.
When you hang the film up you may think you have done something wrong, it usually looks terrible. Just wait for an hour or so and you should find you have some pretty good negatives.
The correct time for C41 processing is 3'15" at 37.77 C (38C). I note that Unicolor give different temperatures for different ways of processing. What they seem to be doing is allowing for different methods used and how the different methods alter your ability to hold the colour developing bath at a constant 37.77C. Basically if you can determine what your start temperature is and what your finish temperature is and then calculate the median temperature best for your method that keeps the developing bath as close as possible to 37.77C is where you should be.
Once you have established a developing regime that works for you, things will be simple and hopefully your photographic world will be filled with vibrant colour images.
Mick.