Some elementary questions about E6 processing

I am getting set up to process E6 (Velvia 50 and 100) in 120 rolls. I have a water bath which I am temperature stabilizing at 100F using an aquarium heater element and a cheap PID controller. I have found that an oral digital thermometer is very good for temp. measurements at ~100F and using a cheap ($9 on ebay) circulating pump maintains the temp. uniformity of the bath extremely well (less than 0.1F variation between any two points in the bath). I am using an SS tank and, as a novice, I did a practice run on a BW roll (Tmax100) and it came out perfectly (beginner's luck). I will practice on a few more rolls before the E6.

My question is about chemistry. In Seattle, one can get the Kodak 5L single use kit locally and also by mail from Adorama. One can also get the Tetenal (3 bath) kit by mail. I did some searching of the forums and didn't see a definite preference for one over the other. It seems that the Kodak kit might be a little cheaper in the long run, but one might be able to re-use the Tetenal chemicals. Any advice along these lines would be much appreciated.

Also, even though I have read the document (in the Z119 series) about storage, is the storage time for opened bottles of developers really as short as 1 week? How much is this increased using accordion-type bottles or filling with dry nitrogen or CO2?

Thanks!

Warren Nagourney

I have used both - Tetenal faster as youd expect but I've heard it isn't as archival as the full kodak system - thats about it, I'm a beginner also ...

Off topic maybe - does the Aqaurium heater work via a kind of PWM system (on and off/duty cycle) - what PID controller ? one suited for this application or are you translating it from motor controls somehow ?

I use the EK 5 L kit and it works fine for me. You can mix up only what you need for a specific run, and the concentrates will keep in tightly closed bottles for months. Temp is critical for the first three steps, and is therefore critical for the first rinse as well. Good luck.

Bob

FWIW, I do my E-6 without water pumps or heaters; I just rely on my water bath to keep the heat constant enough, in conjunction with adding a bit more hot water by hand. More effort on this score might improve quality, but my method works well enough to satisfy me.

As to the rest, I've used the Kodak E-6 kit and two or three brands of 3-bath kits, and none of the 3-bath kits I've used has produced results as good as the Kodak 6-bath results. This goes double when I've attempted to re-use the 3-bath kits; quality goes way down on re-use, in my experience. Add to that concerns about how archival the results are, and the fact that the Kodak kit is less expensive on a per-roll basis, and it's just not worth it. The one advantage of the 3-bath kits, IMHO, is that they take less time to do the processing. The actual process times, if you add them up, differ by just a few minutes, but then there's extra preparation and clean-up time for the 6-bath process, and that can be a drag.

As to shelf life, when it's stored in stock form (undiluted), the Kodak kit lasts several months, at least. The kits I've bought have expiration dates stamped on their side, usually about a year in the future. (IIRC, I bought one of mine from Adorama and another from Unique Photo.) Mine have both lasted beyond their claimed expiration dates, even after being opened. If you shoot enough E-6 to be worth doing your own processing, you shouldn't have to worry about the chemicals going bad unless perhaps you buy a kit very close to or after its expiration date.

I use minilab chems, more economical as you get a lot more of it.


I havent tried Fuji stuff yet, but Kodak E-6 colour developer and Flexicolor stuff seem to last a very very long time in their bottle concentrates. My E-6 CD expired in 2005, and its still like new.

I use a plastic tank rather than steel, as plastic is a brilliant insulator, steel the worst insulator just about, a pre-bath in hot water to warm up the tank, and that keeps my temp where I need it once I heat up the developer.

Otherwise for a consistent water bath, steel tank will heat up faster, so there will be less waiting.

Thanks very much for the responses.

@ Nick. Yes, the heater is PWM, not proportional. Since the thermal time constants are so long, the controller is a conventional PID (Proportional-Integral-Differential) unit, which is a linear system. The heater is controlled using a relay (mechanical or solid-state) and comes on and off every several seconds. The controller is one of the huge number of Chinese-made PID controllers sold on ebay (I think my unit is a CD-101). I got the inspiration for this from an article about a homemade sous vide system http://seattlefoodgeek.com/2010/02/diy-sous-vide-heating-immersion-circulator-for-about-75/.

I am glad to see that the two developers will last a long time in their original containers after a portion has been used. Does it help to fill the space above the liquid with some non-oxidizing gas?

Actually, my number of rolls per week is not that great. I am doing this to avoid the annoyance of dropping the film off (and picking it up) at the only E6 processor that I know of in Seattle. Also because it is fun and it is nice to be in total control of the photographic process. The temp. controller project gives me an excuse to do some electronics again after being retired from academic physics for several years.

One of my concerns is about chemistry availability. I get the sense that the local provider might stop carrying the EK kit soon - they only sell one or two a week. Shipping from Adorama is about $20 and there might come a time when the mail order houses stop shipping it, particularly if the worries about shipping "hazardous materials" increase. Thus, I considered the Tetenal kit a possible back-up (also there is an Arista kit).

Cheers,

Warren N

Good to see yet another interested in home E6 processing, seems to be more and more people doing it these days. Sounds as if you have a pretty good setup for processing; as far as chemicals go, I'd say go for the Kodak kit hands down. A 3 bath E6 process is a compromise as others have mentioned.

For longevity, the Kodak concentrates seem to have a fairly good shelf life but once you break the seal, the clock starts ticking much more quickly and more so again for the working solutions. Myself, I get around this by freezing my working solutions in a chest freezer. This allows me to mix the entire kit at once so as to avoid almost all the mixing and contamination errors that can occur from attempting to divide and mix smaller quantities.

I just came across a long lost set of working solutions I had mixed up back in Feb. 2003 at the bottom of the deep freeze. I threw 'em in the Jobo to temper (takes a little longer from frozen of course) and processed 2 rolls of E100g and they came out perfectly. I actually have 8 frame "control strips" I made up years ago from bulk loaded Kodak and Fuji film that I throw on the end of a reel from time-to-time to check the consistency and this strip was no different than the others. Of course this is by eyeball method but I can't detect any difference even under a loupe. Anyway just an idea and from experience, sure beats trying to transfer concentrates to ever smaller bottles or using marbles to take up air space or keeping tanks of Argon gas hanging around the house.

Thanks, Rob, for some interesting suggestions! How do you prevent the container from bursting when it is frozen?

Could you elaborate a little more on your test strips?

Thanks.

Warren N

warrennn said:

I am glad to see that the two developers will last a long time in their original containers after a portion has been used. Does it help to fill the space above the liquid with some non-oxidizing gas?

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I imagine it would, according to some, they go off much quicker once open, however my Tetenal C-41 kit (while not Kodak E-6, it just serves as demonstration) lasted a bit over 12 months in the open concentrates without something like nitrogen gas etc - though they didnt go off at that point, I simply ran out.

In any case if youre worried about it, nitrogen is cheap.

I dont imagin availability is a huge issue, as even here in Aus, I can order Fuji or Kodak chems individually meant for minilabs.

You could mail-order (online) the same stuff, I think they start in sizes of 20 litre kits though, rather than 5.

warrennn said:

Thanks, Rob, for some interesting suggestions! How do you prevent the container from bursting when it is frozen?

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Plastic bottles. I use simple 500ml water bottles and fill with 330ml of chemistry so there's plenty of room for expansion. So from a 5L kit, I end up with 15 sets of working solutions for a total of 90 bottles which go in the deep-freeze. When I process, I simply reach in the freezer, take out 6 bottles and throw them directly in the Jobo's tempering slots and they thaw out in there while the water bath is heating up. This way, I'm not mixing chems every time I want to process a few rolls of film. The chems are mixed up all on one day and the graduates and other mixing junk are put away until next time and I'm not worried about my concentrates oxidizing.

As for mixing, this is easy as well. I have 6 dedicated, square water jugs with pour spigots that I mix my working solutions in. So for each chem, I simply measure in 3L of water, dump the whole bottle of each concentrate in its respective jug and stir, then fill each jug to 5L as per Kodak's instructions. Since I'm dumping the full contents, I'm not measuring each concentrate and only use my graduates for measuring out the water. This eliminates the possibility of cross-contamination from improper rinsing of my graduates between chems.

Once I have the 6 jugs of working solutions mixed, I need to get them separated into the smaller water bottles for the cryogenic treatment. This is also easy as I have lines marked on the side of each of the 90 bottles denoting a level of 330ml. It's simply a matter of sticking each one under the jug's pour spigot and pushing the lever until it fills to the level of the line on the bottle. Again, no need to use my graduates to measure and no chance of cross contamination. The bottles are re-usable and I have each one (and its cap) labeled with the proper chem name. Sounds like a lot of work but mixing is about 2 and a half hours from start to cleanup and depending on how much film I shoot only once every few months.