Tetenal Colortec C41 question

[miha]

Tetenal Colortec C41 instructions say 1 litre is good for 4 rolls at 3'15'', and should be extended to 3'30'' for the next 4 rolls. They give times for up to 16 rolls.

I will develop 4x5 manually in a Jobo, 270ml needed for 6 sheets at once. Since 1 roll equals 4 4x5' sheets I can develop 2 runs (= 12 sheets = 3 rolls) at 3'15'' before I add another 15''. I would not go beyond 18 sheets altogether. That means 3 runs, the first two at 3'15'' and one additional at 3'30''.
Another option is to mix 330ml (270ml is needed) only, which is good for one run (= 6 sheets) and dump it. This will give me 3 runs (3x330 ml = 1L) or 18 sheets too, each time in fresh chemistry.

Which option should I choose?

 

[Tom Kershaw]

I would be cautious about over using C-41 developer. One disadvantage of these kits is that the bleach has double the capacity of the developer. Kodak's capacity statements are conservative but I would process no more than 5 rolls of 120/135 equivalent per litre of developer in total. Also take into account higher ISO films require more developer capacity, so 5 rolls of 100/160 ISO film per litre might be acceptable, whereas 3 films per litre would be a better option for 400 or 800 ISO film.

Tom

 

[miha]

Hi Tom, 18 sheets only is my intention, this is less than 5 rolls. Film is Ektar.

 

[Rudeofus]

I think you should pursue two options:

1. Mix three batches of 333ml each and use them up one after another. These 333 ml batches are good for about 5 rolls, which equals 20 sheets, which means three dev runs with 3:00, 3:15 and 3:30.
2. If you have a lot of sheets to process, you should seriously consider their 5l kit which is a lot cheaper per batch. Once you have a 5l kit, it makes sense to mix 275ml at once which gives you 18 batches. These batches can, again, be each used for three dev runs with 3:00, 3:15 and 3:30.

 

[miha]

Hi Rudeofus, a 5 litre kit is too much for Ektar in 4x5 and my needs* as the concentrate once the bottles are opened lasts 12 weeks only.

*That's 400 Euro of film in 12 weeks!

 

[Rudeofus]

I have made the observation, that the concentrate lasts a lot longer than the bottle claims. This is especially true if you use a shrouding gas to drive out air from the half empty bottle. Tetenal offers a simple spray can for that. I've had Tetenal E6 last for over a year reliably with this method.

 

[miha]

Thanks, good to know. I have a can of Protectan somewhere in my DR.

 

[Rudeofus]

Thanks, good to know. I have a can of Protectan somewhere in my DR.

One thing I should mention: if you make partial mixes of these concentrates, be sure to also protect the BX2 bottle. It contains Ammonium Thiosulfate (which would be quite stable on its own), but also Acetic Acid, and this makes the Ammonium Thiosulfate go bad quickly unless protected from air. The only concentrates which do without protection are BX1 (the purple one) and STAB.

 

[miha]

Thanks again Rudeofus. Still, I'm not sure whether I should mix up 1 litre of each chemical and adjust the time for the third batch of film or is it wiser to mix them fresh for each batch of films to be developed? The downside of mixing fresh is that a need a couple of small graduated cylindres to be able to measure small amounts of chemicals (down to 33ml in fact).

 

[Rudeofus]

Small batches give you more degrees of freedom and less inclination to do a dev run with expired working solution. Glass ware is cheap and easily available, and it makes me look more important

 

[miha]

And no need for extra bottles either

 

[Photo Engineer]

Kodak has a complete chart of times versus square footage of film processed. You might want to look it up. It should work for all compatible C41 processes.

PE

 

[miha]

Hi PE, thanks. I found a chart explaining the capacity for various film formats: http://www.kodak.com/global/plugins/acrobat/en/service/Zmanuals/z131_03.pdf (Capacitiy of unreplenished solutions)

But generally Flexicolor aims for replenishing systems mostly.

 

[Photo Engineer]

Go to page 3.5 for the information you need.

PE