Diluting C41 Developer

bvy · Oct 16, 2012

I have the Rollei/Digibase C41 kit, which makes 500ml of developer. I don't presoak, so with each roll (I'm about seven in), I'm losing some volume. I now have about 450ml of working solution -- not quite enough to cover a 120 roll. I figure I need to add between 25 and 50ml of water. Can someone help me gauge by how much I'll need to compensate in development time? Or is this just a bad idea?

Thanks.

wildbill · Oct 16, 2012

presoak next time.
I wouldn't dilute it for my own work.

Gerald C Koch · Oct 16, 2012

Unlike BW chemistry processes like C-41 must be used exactly as specified. This means no dilution, no changes in temperature, and no changes in processing times. Failure to do this will result in color shifts or poor density.

Rudeofus · Oct 17, 2012

wildbill said:
presoak next time.
I wouldn't dilute it for my own work.

Presoaking your film does exactly the same as filling up developer with water afterwards. I've heard that C41 dev kits are very robust and would assume that a little dilution is not going to hurt. A guy tried to really hit on C41 developer hard in order to achieve lomo style results, but never got those crazy colors, at least nothing that couldn't be trivially corrected post scanning.

GeorgK · Oct 17, 2012

Gerald C Koch said:
Unlike BW chemistry processes like C-41 must be used exactly as specified.

A agree in a way that I am also not a fan of the many "great results with stupid C41 modifications"-threads on APUG.

But: C-41 is usually a constantly running machine process with a seasoned developer, defined replenishment, nitrogen burst agitation, and complex process monitoring. Home processing C-41 will always be just a rough approximation (at best). Under these circumstances, additional dilution of 10% will hardly have any (visible) effect. Especially as C-41 is quite a "strong developer" where slight variations in concentration will have only a minor effect.

@bvy:
Simply add 50ml of a.d. to your 450ml kit (do not mess with too few volume, it's not worth it). Probably add a few seconds (5-10), but not more, to avoid over-compensation.

Georg

David Lyga · Oct 17, 2012

bvy: Just for the hell of it:

Take 100ml of fresh Flexicolor developer. Dilute it 14 times to make 1500ml working solution. Then add maybe 5 grams of sodium carbonate to the 1500ml. Then, at 90F, process C-41 film for 12 minutes in as much of this working solution as you need to develop one roll, using constant, gentle agitation.

You must might become satisfied with the results, and the temp is easier to maintain.

Now, Rollei-Base is not Flexicolor, but maybe the results will be the same as mine, I don't know. - David Lyga

bvy · Oct 22, 2012

Thanks for the responses. With 400ml of developer (less than I thought), I can get coverage in my Paterson tank by placing it on its side. I have a Unicolor Uniroller transport; I'm considering sealing the lid well and placing on there, on its side, for constant rolling agitation. I would cut thirty seconds off of the development time. Thoughts?

Gerald C Koch · Oct 22, 2012

GeorgK said:
A agree in a way that I am also not a fan of the many "great results with stupid C41 modifications"-threads on APUG.

But: C-41 is usually a constantly running machine process with a seasoned developer, defined replenishment, nitrogen burst agitation, and complex process monitoring. Home processing C-41 will always be just a rough approximation (at best).

There is no guarantee that any of these home processinjg kits are anywhere near the official C-41 formulation. In all likelihood most of them aren't unless you are using Kodak's Flexicolor.

maximgrew · Oct 22, 2012

I have used slightly diluted C-41 dev from a Tetanal kit before it was also quite a bit past its 12 roll use I added around 15 seconds for the diluted old developer and you will get useable images it just depends how you feel about whats on the film really if its something you put through a holga then go for it but if not might be worth sending to a lab

and yeah with the tetanal kit you do cut 30 seconds off in a rolling processor so may well be the same for you

bvy · Oct 22, 2012

I posted that rather hastily. Hadn't considered that the tank would be outside the water bath. Still, I might just manually roll it on top of the tempered water and see what happens. And cutting thirty seconds sounds like a good idea.

And, as a matter of fact, they are Holga images. But I do have one of a semi-famous, fully pompous, operatic baritone in costume, that I'd like to see come out.

maximgrew · Oct 22, 2012

haha yeah think rolling in the bath will be your best bet then! good luck!

Athiril · Oct 23, 2012

process in a single reel 120 tank, agitate every 15s, 2 agitations, then hold upside down, next agitation cycle, 2 agitations, hold right way up etc.

You can dilute, it's just sub-optimal results.

+50ml might not hurt it that much though tbh, I'd increase time slightly.

I've seen and tried 1+9 semi-stand (didnt add carbonate though etc) for an hour, very very grainy, but reasonable colour.

Rudeofus · Oct 23, 2012

Athiril said:
process in a single reel 120 tank, agitate every 15s, 2 agitations, then hold upside down, next agitation cycle, 2 agitations, hold right way up etc.

This is the method I used for about 2 months many years ago, and it ruined every single roll I did that way. Some parts of the film will be covered in chemistry longer than others and the negs will show this. Unless I misread your posting, I would highly recommend against it.

L Gebhardt · Oct 23, 2012

Hold onto the roll and order another, larger, kit. Replenish the one you have with the fresh developer if you want to save some bucks.

Athiril · Oct 24, 2012

Rudeofus said:
This is the method I used for about 2 months many years ago, and it ruined every single roll I did that way. Some parts of the film will be covered in chemistry longer than others and the negs will show this. Unless I misread your posting, I would highly recommend against it.

What was your agitation cycle?

Rudeofus · Oct 25, 2012

Athiril said:
What was your agitation cycle?

Fill tank with chemistry
wait 15 seconds
turn tank upside down
wait 15 seconds
turn tank back to normal
wait 15 seconds
turn tank upside down
wait 15 seconds
turn tank back to normal

...

until soup time was over.

Since the film was only about 10% submerged in the color developer when the tank was upside down, these 10% received more development than the rest. Result: useless pics unless the frame could be cropped. Happened when I was a complete noob and on my own, and took me quite a few rolls to figure out and made the 5D look very attractive for a while

Never again ....

Athiril · Oct 25, 2012

10% coverage is a LOT less than 90% coverage. And you need to agitate on as well as cycle, not just cycle.

Rudeofus · Oct 26, 2012

Athiril said:
10% coverage is a LOT less than 90% coverage. And you need to agitate on as well as cycle, not just cycle.

Turning a Jobo 1510 upside down will not keep 90% of the film roll submerged if you fill the tank with the recommended 250ml. Unless you fill the tank to the brim with developer, I would strictly recommend against turning it upside down except for very short times during agitation, and for pouring out the developer, of course.

My conclusion from this disaster was that film is either completely submerged in or completely out of the developer, or it can be guaranteed that all parts of the film are submerged/out of the dev for the same total amount of time, like in a rotary processor.

destroya · Oct 28, 2012

L Gebhardt said:
Hold onto the roll and order another, larger, kit.

+1

Diluting C41 Developer

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