Replinishing e-6 Bleach, downsides?

[jerry2]

A few questions regarding replenishing the bleach:

 

1) Is there any disadvantages or risks associated with replenishing the bleach?

 

2) Is it as simple as people make it out to be?

 

3) Is the $ savings really 50% for the next run of e-6?

 

4) Do most commercial labs replenish their bleach? I assume they do.

[g._armour_van_horn]

Look at z119-2.pdf, page 3. There you will see the replenishment rates Kodak recommends for all solutions. The two developers are 200 ml per square foot of film. Bleach is 20 ml, everything else is 100 ml. Even with the bleach replenisher being twice the concentration of the working tank solution, you're cutting the amount of bleach used per roll of film by over 80% compared to one-shot.

 

Commercial labs replenish every solution. E-6 processors have aerators built in to the bleach tanks.

 

Here's my system with the Photo-Therm. The system uses 2 liter holding tanks for all solutions, and I have a matching tank for the recovered bleach. (The machine has a switch to save the bleach or not and dumps it to a separate hose if the switch is on.) I make up one gallon of fresh working tank solution and pour it into a five-liter poly jug. After letting the liquid stop sloshing around the first time, I took a Sharpie and made a dashed line all the way around the jug at the 1-gallon level. (Note that it doesn't make any difference what level that is, just that you have one. You could use a smaller quantity but then you couldn't go as long before needing to replenish it.)

 

I have an $8 aquarium pump with a 1/8" line going into the bleach holding tank. I use a cheap timer to turn that on for two hours a day. As I use the bleach, I fill the holding tank from the big jug, and I dump the recovered bleach back into the big jug.

 

I used to keep a sticky on the front of the machine to make hash-marks for each roll of film, now I just log the number from the most recent TwinCheck when I replenish the bleach. Looking back over my mix log, it seems I do this every 30 to 40 rolls.

 

At that point, I calculate the amount of replenisher (12ml per 135-36 run) and pour it in the big jug. Then I take the holding tank out of the rack and pour the contents of that into the jug, as long as it does not take me over the line marked. If that did not fill it up, I then take the recovered bleach tank and use that to bring the big jug back up to the gallon level. The rest of the recovered bleach is then discarded, and both bleach tanks are thoroughly rinsed out.

 

Depending on how much time pressure I'm under, I sometimes pour a liter into a tall graduate and check the density with a hydrometer. It's always been well within tolerances, so I'm doing this less and less often.

 

Look at the chemical costs and do the math yourself. You'll instantly see the pain involved in paying for extra bleach. Then note that the bleach is the least concentrated of the concentrates, which means that you pay more for shipping it per gallon of working solution than for the others. Also, it's hazardous enough that B&H won't ship it at all and I believe Adorama won't ship it by air. All of this convinces me that optimizing the bleach is a worthy thing.

 

Whether it would be a full 50% savings in your exact situation can only be calculated by you after you've logged a few dozen batches, and depends on a host of things like your location and choice of vendors and even the choice of tanks you make. (The 1500-series tanks will use less chemistry than the larger tanks, I think, the replenishment advantage would be less if you use a smaller charge of solution per roll.) But whether the actual savings work out to be 40% or 60%, it's easy to see that it's in that ballpark.

 

Van

[jerry2]

Van, thanks for the nice response..... on the economic front, obviously it makes sense...but what is the possible downsides? None?

[alan_rockwood]

Van,

 

Is there a way to do this with a plain vanilla Photo-Therm, or do you need an "R" variant machine?

 

Alan

[g._armour_van_horn]

Bill, why do you look for a downside when following the manufacturer's recommendations? Replenishing the bleach at the rate described in the manuals is how it's supposed to work. Because of the lower costs of the other solutions, added to the higher replenishment rates for them, there isn't much disadvantage to using them one-shot, but replenished is the way the process was designed to work.

 

Alan, I have no idea what an "R" variant is, I don't have one. Mine is an SK4G, as far as I've seen looking at various models on the Photo-Therm site and when offered on eBay, the recovery for the bleach is just a basic part of the design.

 

Van

[jerry2]

Van, I agree..... I was thinking more in terms of messing up the replenishing, or contamination, etc. I guess if the savings justify you, you learn to do it right...

[alan_rockwood]

Van,

 

Thanks for the response. As I go back and read the manual more thoroughly I see you are right. Saving of bleach (or blix or fixer, depending on whatever) is a standard feature of the machine. I have never tried color film or slides in my Phototherm SK4G, and I made some incorrect assumptions about the machine... good thing I haven't run any color film or slides yet.

 

The R variant will save both fix and bleach: http://phototherm.com/sk8rh.html.