Does Ferricyanide bleach exhaust? If so when?

[mohmad khatab]

Yes I feel sad to throw away used chemicals when I know they have much life still left in them.

Would you have me throw away all of the food left after a meal? When I know that I can easily save the extra food and eat again the next day.

Or if I buy new clothes and they become dirty, would you have me throw them away and buy more? When I could very easily wash them to a like-new appearance and wear them again. Is that not wasteful?

So why must I throw away my chemicals when I know that I can easily repair them and use them again?

Momad, I must confess that I'm speaking to you in humor, to pretend as if you are wasteful, which I know that you are not.

On a serious note, my experience is from a photofinishing lab where we used over 5,000 gallons of replenishers every day. That is about 20,000 liters per day. So we have the opportunity to reuse some of this, why not? Everything we can reuse is something that doesn't have to be disposed of, and something that doesn't have to be bought new. And so the money saved can go to pay employees (but more than likely to company profit).

Now this sort of saving is not for everyone, because it takes extra labor and equipment to do it. So you don't want to spend five dollars of work to save one dollar of chemicals. But if your five dollar of work can save, say, five HUNDRED dollars of chemicals, then shouldn't you do it? (Of course you should.)

As a very rough estimate, comparing a typical user of mix-it, use-it, and throw-it-away photo chemicals versus a commercial lab using best practices of replenishment, use of squeegees after every tank, and regenerating bleach and fix, I would say that the commercial lab can have a chemical cost, per roll, about ten times lower. Note that I did not specifically calculate this, just a rough guess from past experience.

Yes, yes, dear brother ,, I know that you speak with humor.
- But the difference is great, dear brother. The difference is large between the quantities produced by a professional laboratory and between the quantities produced by a home user.
Basically, there is no comparison.
So I see our friend OP has consumed his valuable time reading, researching, reviewing, checking, and ultimately the value of those chemical raw materials is worth nothing.
- I am a really poor man, and it suffices to tell you that I am Egyptian, and this implies that I am poor and not ashamed of that.
But sometimes time is more precious than the cost of these materials, and sometimes the presence of this chemistry in the home becomes a burden and takes place.
So I am speaking out of public interest ,,
I am not a rich man and sometimes I mix two chemicals in order to give the same effect as another little expensive substance ,, and all of this in order to save money ,,,
But in that case ,, I try to renew the chemistry only once and if I have doubts about its effectiveness, I immediately get rid of it without regret. And in this case as someone who gets rid of his food waste after digesting it and it is not suitable for eating
God bless you brother

 

[GBS]

if I have doubts about its effectiveness, I immediately get rid of it without regret. And in this case as someone who gets rid of his food waste after digesting it and it is not suitable for eating
God bless you brother

HA! This is a good one about food waste! I simply don't like to waste. I like spending an hour or two researching and discussing reuse, even if doesn't save me a dime. It's a blessing and a curse.

I was in Egypt twice for a very short time, once as a young boy, then again as a young man. It's beautiful and the people were very kind. I took some of my favorite photographs there.

 

[GBS]

Table 7.2 says that SR-29 bleach replenishment rate is 200ml of replenisher per 100 feet of 35mm film which translates into 11g of Ferricyanide and 7g of Bromide.

Hey @Raghu Kuvempunagar--thanks again for the clear direction where to find this info. It's been a big help and I'm still embarrassed I missed it so easily.

One tangential question to see if I'm reading that chart correctly. Can I assume the developer can process 100'/L without replenishment? Or does the developer need replenishment after each roll? (~45ml for each 36exp processed)

Ultimately, I'll be working with 1L and I'm curious about a potential time increase compensation which I haven't found commonly published for ECN-2.

Thanks a lot

 

[Mr Bill]

One tangential question to see if I'm reading that chart correctly. Can I assume the developer can process 100'/L without replenishment?

Hi, I'm obviously not Raghu, but can probably give a reasonable answer. It's "no."

If you actually tried to process 100 ft of film, by hand, using 1 liter of developer, you would probably finish up with only about half your developer left. And it would be suffering pretty badly from "exhaustion."

To put some of the things in the H-24 manual in perspective, it's written in support of professional use of the products, where one wants to have a consistent product always coming off the machine. And you only get this with more or less constant replenishment. Now, the size of the developer tank has a lot to do with things, where a large tank size gives you a substantial buffer. But with only one liter of developer, you would ideally be replenishing every roll or two.

Ultimately, I'll be working with 1L and I'm curious about a potential time increase compensation which I haven't found commonly published for ECN-2.

These cine-type processors don't even have the capability of compensating with development time. If you were to ask one of the operators of such a machine about such a thing they would probably just ask, "why would you want to do that?" If you said it was to compensate for lack of replenishment, they'd ask, "why don't you just turn up the replenishment rate?" It's a completely different world from what most people here are familiar with.

 

[GBS]

It's a completely different world from what most people here are familiar with.

Thank you--I totally get that. To be clear, processing and printing B&W stills in my bedroom closet as a young man ultimately led to a career in the film industry; I have several thousand feet of raw 16mm in the fridge now. I am learning a lot about development chemicals, time, replenishment, all the way down to separate rollers and tanks in the machines that I never had to pay paid attention to. The fundamentals of exposing and processing B&W, C-41, and ECN-2 are all something I have experience with, at least by proxy once-removed. I've never processed color it myself, but I know more than enough to be a thorn in someone's side when I'm ready to learn. I appreciate your, end everyone's patience and input.

If you actually tried to process 100 ft of film, by hand, using 1 liter of developer, you would probably finish up with only about half your developer left. And it would be suffering pretty badly from "exhaustion."

But with only one liter of developer, you would ideally be replenishing every roll or two.

Thanks a ton! These are both simple and clear. Common sense led me to believe replinishment would have to be done incrementally. That makes sense. Now, don't be mad at me if I experiment with extended time in place of replenishment. I realize motion film processors have a massive volume buffer and are not built to time-compensate. I think experimenting with the documented compensation times for C-41 is a great place to start. If it's remotely informative, I look forward to sharing my findings with the community.

I didn't mean to hijack my own thread. I asked the question about developer, using the previously mentioned chart to make sure I was understanding it. Thanks again!

 

[Raghu Kuvempunagar]

Now, don't be mad at me if I experiment with extended time in place of replenishment.

Just curious to know. Are you going to be processing one or two rolls (36 exposures) at a time or entire 100 feet in one shot? If it is the former then you may want to check this post by @fdonadio which says 1 litre of developer has a capacity of about 12 rolls without replenishment.

 

[NB23]

Why do you want a constant renewal to infinity?
You should get rid of him without regreting ..
I keep it somewhere with a swamp full of insects and rodents ,, this is the best help for the environment.
Then I prepare a completely new bleach solution.
- What is the problem ..?
Do you feel sad when you get rid of used bleach solution?
Why do not you feel this sad when you get rid of the consumer developer.?
You must get rid of old chemical solutions when you feel that they have produced the film quantities that you must actually produce.
Life must go and feel that there is a crew of new solutions that is somewhat happy.

Why get rid of it if it’s still active?

Or to make a parallel with your example about life: why suicide if you’re alive?

 

[GBS]

Just curious to know. Are you going to be processing one or two rolls (36 exposures) at a time or entire 100 feet in one shot? If it is the former then you may want to check this post by @fdonadio which says 1 litre of developer has a capacity of about 12 rolls without replenishment.

@Raghu Kuvempunagar thank you for the question and clarification--super helpful and important. Indeed, I will be doing one or two rolls. I'm aware of the 12/L target with home kits. I was curious about replenishment rate in general--which you and others helped clear up, thank you! Replinishing doesn't seem to make a ton of sense for me right now simply because shelf-life of the replinisher--it'll go bad as fast as the developer and I'm not shooting that kind of volume. Maybe I'll have time someday if I stop asking so many questions-ha!

All that said, at some point I'll test mixing micro amounts of replinisher (say, 10-20%) and replace 90ml of developer every 2 rolls. (That would mean my scale needs to be accurate to 0.01, especially for the Sodium Bromide and Sodium Bicarbonate, so I'll cross that bridge later, but micro replenishing is something I'm at least interested in one day down the line).

Once I'm happy with the basics of ECN-2 and have a consistent workflow, I'll probably do some time compensation tests.

But again, I think I'm racing the clock in general with 1L. However, if I can mix 250mL of dev and micro-replenish, that might work. Again, all this needs to be checked and tested. I'm working on my starting point now. Thanks a ton!

 

[AgX]

Thank you for this digression into terminology.

More so as terms may be used even differently. So a german manufacturer called a replenisher "Regenerator".

 

[GBS]

Hi all!

Placed an order for ECN-2 and C-41 chemicals yesterday. Getting close! Again, I'll be working with a friend to do a series of side-by-side stocks and development tests, mostly with Vision films. I used an ECN-2 kit for some basic development tests and am very happy with the result so far.

I'm coming back to this thread to see if anyone has further guidance/experience with hard numbers when using this type bleach--even with C-41?

Considering my workflow ... developer > water wash > stop > water wash > bleach ... I would assume the bleach will remain fairly free of developer contamination.

Using the Kodak ECN-2 publication, and assuming the replenishers all have a somewhat-relative potency, it appears as though this bleach will last about 4x as long as the developer. (I will not be replinishing, but I am using the rates as a comparison.)

Many say ECN-2 does about 12 35mm/36 rolls per L. Is it safe to assume this bleach will do 4x that with water/stop/water in between developer and bleach? (or even 3x to be safe. I'd like to minimize my waste and environmental impact.)

Thanks so much!

 

[koraks]

I never measured the capacity of the ferricyanide bleach, but it seems to go a long way. I think I got close to the 36 rolls/liter figure before I stepped away from ecn2.
Btw, I'd suggest leaving out the water wash after the developer. It doesn't have a function and if anything, it's counterproductive. Stop right after developer, and I'd then do 2 consecutive water washes to get most of the developer and stop out of the emulsion before the ferricyanide bleach. You don't want significant quantities of sulfuric acid (ecn2 stop) to carry over into the bleach.

 

[GBS]

@koraks Thanks a ton—as always. And noted on the water wash after the developer. 36/36 is plenty. Thanks a lot