Dumb Question on Mixing Tetenal C41 2.5L Kit

[JWMster]

Annoyingly dumb question: Looks to me like you can actually mix up less of the chemistry at one time. Instructions suggest 2500 ML can also be mixed as 5 X 500 ML. Yes, it may sound dumb to ask, but coming from B&W developing, it's all new over here and I need to order separate containers for color chemistry, so I want to confirm that 500ML or 1000ML is an amount that folks actually mix up (rather than mixing the whole thing in one batch). Seems to make sense, but I take less and less for granted these days. Thanks!

 

[MattKing]

Are you sure that isn't just a recommendation for storing the 2500 ml in 5 smaller bottles?

 

[JWMster]

Matt: Thanks! That's actually a careful and considered question. Here's what I found:

Page 4 of the Instructions for Tentenal Colortec C-41 Kit 2,51 Art. Nr. 102230: "Parial mixing is possible, e.g. for 5 X 500ML."

So I think it is indeed about mixing. Question is whether this is something folks actually do? Tetenal (per earlier thread somewhere nearby) has confirmed that the mixed chemistry's usable life can be extended by refrigeration (to wit: freezing). I'm just trying to figure out what size containers make the most sense on the basis of what folks actually do in the real world. (Took me long enough to figure this out in B&W, so I'm hoping to speed the cycle a bit with C-41 before blowing too much $'s).

 

[Rudeofus]

When I do RA-4, I typically start with 500-600ml. Small test strips need 80ml, whereas 8x10" sheets need 180ml of process liquid. After each run I pour the chems back into their container for further runs. As more and more paper is processed, more and more CD is carried over into stop&wash, and the amount of CD left goes down and down until there is not enough CD left to cover an 8x10" sheet, at which point my session is over.

So yes, 500ml would be a typical amount for me to mix. If you plan on not reusing your chems, you might as well mix the whole 2500ml at once - you'll need them.

 

[Down Under]

I've used the Tetenal C41 kits for many years. The 1 liter kits were a good buy in Australia until they mysteriously became "unavailable" about 18 months ago from Vanbar, my usual suppliers in Melbourne and I changed to using the Rollei C41 kits (basically the same chemistry under a different label). I then bought a 5 liter Tetenal kit (much more expensive) and used about half of it before I went traveling in Asia for 12 months - when I returned, the three color developers (Parts 1, 2 and 3) had gone bad and the kit was unusable.So wasted money. Lesson learned, I now only buy the smaller kits.

But I digress (again). Back to the points made by the OP.

Yes, Tetenal (in the booklet) does recommend mixing 500 ml at a time. But with my Jobo, I use 250 ml at a time, easily mixed by dividing the total mmls in the kit by 250.Say 2.5 liters = 2500 ml, so 10 mixes of 250 ml each.

I then use one mix (250 ml) to process five films, all in one session. It's best not to keep the mixed chemistry lying about too long even in sealed bottles, to ensure consistency in your results.

Processing times will change as you work through the films. Longer times overall. It's all explained in the Tetenal booklet.

After five films, dispose of the chemistry (Tetenal advised you can use the stabiliser longer term but I'm no longer sure about this) and remix another 250 ml when you have five more films to process.

More than a decade ago I emailed Jobo USA about a small issue I had with the Jobo (mine is an Duolab, the super cheap model they sold very briefly in the late 1990s-early 2000s) and someone there gave me some good advice about C41 processing. I was told to use more changes of water than Tetenal recommends for the final wash and also a weak (say 2%-3% dilution of stop bath after the color developing, followed by a water rinse. I've done this ever since and see no reason to not continue.

Some users like to either put Photo Flo in the stabiliser or do a final soak in same before hanging the color films up to dry. My Jobo contact told me to never do this,as the last Photo Flo rinse dilutes the stabiliser and reduces the protective effect of this chemistry on the film.

I'm in Asia now, and I have between 30 and 40 rolls of color negative films to be processed - C41 processing in Singapore is super cheap compared to Oz, S$4.50 per roll, but alas! I won't be visiting there), so when I return to Oz soon I will buy another 2.5 liter kit, and freeze the leftover (unmixed) chemistry per advice read in this thread. Thanks to whoever posted this, I wish I had done it last year and saved half the "lost" kit...!

Hope this is useful. With a Jobo, color temperatures during processing are never a problem and my results were/are always uniformly good.

Read the manual from cover to cover!! (Or at least the sections in your first language.)