Importance of correct mixing temperature?

BennehBoy · Nov 11, 2013

I'm having real difficulties maintaining a good mixing temperature for my digibase c41 colour developers - it requires a temperature of 49C

My water heating system maxes out at 51C, by the time my water bath is full it's already dropping below 49C.

I don't have access to distilled water so am using a Brita filter, bringing the filtered water up to temp is taking way too long (so I've been microwaving it!).

I've been using a plastic jug to mix the chemicals sat in the bath, the jug likes to float, so will be replacing with a glass one - presumably a glass jug will help hold in the heat and keep me on track whereas the plastic one is probably insulating too much?

Any and all ideas welcomed.

Assuming my mixing happened below the target temperature, should I expect problems?

AgX · Nov 11, 2013

No, as long as the result is a clear solution.

mnemosyne · Nov 11, 2013

I am by no way a C41 expert, but have mixed Digibase chemistry at temperatures below 20°C and haven't encountered any irregularities. Also, I had a look at the mixing instructions of some pro Fuji C41 chemistry and it doesn't even bother to prescribe a temperature for mixing. So I think the temperatures in the Digibase instructions (which are lacking in many ways, IMO) were simply chosen for practical reasons, based on the assumption that this will get your ready working solution in the 40°C ballpark. On a side note, make sure you include a proper rinsing step after fixing, this is important for long term stability, even though it is not mentioned in the Rollei instructions. In case you plan to re-use the solutions consider an additional rinse between bleach and fix and also a quick rinse or weak acetic stop bath between developer and bleach.

BennehBoy · Nov 11, 2013

Great, was in a bit of a panic!

BennehBoy · Nov 11, 2013

mnemosyne said:
I am by no way a C41 expert, but have mixed Digibase chemistry at temperatures below 20°C and haven't encountered any irregularities. Also, I had a look at the mixing instructions of some pro Fuji C41 chemistry and it doesn't even bother to prescribe a temperature for mixing. So I think the temperatures in the Digibase instructions (which are lacking in many ways, IMO) were simply chosen for practical reasons, based on the assumption that this will get your ready working solution in the 40°C ballpark. On a side note, make sure you include a proper rinsing step after fixing, this is important for long term stability, even though it is not mentioned in the Rollei instructions. In case you plan to re-use the solutions consider an additional rinse between bleach and fix and also a quick rinse or weak acetic stop bath between developer and bleach.

I'll be using an ATL 1500, and this is my first time doing C41 and using the machine in anger...

Although I've done some clean cycles and dummy runs using water through the ATL, the 3 bath C41 process only appears to do rinse cycles between certain baths (not all), is there a way to program extra rinses in???

BennehBoy · Nov 11, 2013

Actually, just checked the program and it rinses before and after fix...

BennehBoy · Nov 11, 2013

Well, just done 4 rolls of 135 and they all came out really well

mnemosyne · Nov 12, 2013

For the record: I found some more elaborate Fuji C41 documentation and it says the temperature of the liquids should be between 20°C and 30°C. So actually, Rollei is out of spec when they say you should use 50°C water to prepare the solutions.

Water Temperature
It is important that specified water temperatures [that is 20°-30°C] be maintained when mixing chemical concentrates.
Excessive high temperatures may change chemical properties. Low temperatures may cause
insufficient solution mixing.

more interesting bits regarding storage temperature:

Chemicals existing in replenishers and working tank solutions may
precipitate out of solution at temperatures below 4°C.
Therefore, it is recommended that mixed chemical
solutions be stored at temperatures above 16°C and
below 30°C. Storage in temperatures exceeding 30°C
may degrade solution performance.

source: Fujifilm C41 Processing Manual, 4th edition 2009, pages 29 and 45

AgX · Nov 12, 2013

The Maco data sheet refers to 120°F/49°C for the added water only.

Obviously, as Mnemosyne already hinted at, this is advised as to yield a working solution, when employing concentrates of room-temperature, in the range of 100°F/37.8°C which is the temperature to process at.

Such a procedure will enable one to start more or less directly as one saves the time to warm-up the processing solutions in a/the water-bath, but instead only needs small corrections by eg. rinsing the jug with made-up working solution with warm or cold water.

BennehBoy · Nov 12, 2013

Thanks for that info, was going to fridge store my working solutions, but will just keep them in a dark cupboard.

The only problem I now face is stabilisation...

I've got 1 litre of stab mixed up and dunked the reels from my 2553 into a spare 2830 drum filled with the solution, unfortunately it doesnt cover all the reels... I just did 2 reels at a time.

Should I even be putting my reels in stab? (I cleaned them with very hot water from the kettle afterwards)

What works for you guys?

AgX · Nov 12, 2013

Freezing might be an option if you get everything in solution again. Decades ago there had been an extensive test in a german magazine and the processing results were according to the standard if I remember right. But anyway, the solutions may have changed concerning compounds meanwhile.

Final bath:
What works best for you. You may also put the stabilizer bath in a open container, twist-open the reel and let fall the film into the solution.
You only should avoid scratching the film in the process of taking it off the reel to having it dried.

BennehBoy · Nov 12, 2013

I wonder if the digibase stabiliser can be bought seperately, 2 litres of solution would be a much better way to go for me.

As for freezing the working solution, I intend to exhaust it by end of the week. I'll typically be doing runs combining a mixture of 4x5, 8x10, 135, & 120, and I almost always have an equivalent of 20 rolls backlog, which should be about what I can get from 1L of working solution without pushing my luck too hard.

I've got 12 rolls of 120, 4 4x5 sheets, and 2 8x10 sheets left to do before I move on to my E6 backlog...

Terry Christian · Nov 12, 2013

If you don't have enough stabilizer to cover the reels, try rolling the drum continuously on its side so that the reels get evenly bathed in the stab during the couple of minutes they need to be in there.

BennehBoy · Nov 12, 2013

Terry Christian said:
If you don't have enough stabilizer to cover the reels, try rolling the drum continuously on its side so that the reels get evenly bathed in the stab during the couple of minutes they need to be in there.

I did this too, but it produced a lot of foam - that said none of it was evident on the negs.

BennehBoy · Nov 14, 2013

For anyone interested here's a scan of a 4x5 neg I did today:

Hope I've not gone against any image size limits..

Importance of correct mixing temperature?

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