Minimum Quantity of Perceptol Needed

[Sal Santamaura]

...Until now we can't come to any conclusions about the capacity of Perceptol when used one-shot...

Not "we." Some of us came to a conclusion many, many years ago. And will have no need to knock from within our coffins. If HARMAN doesn't get the answer right 40 years hence, it won't matter. The facts are as they've always been.

 

[mnemosyne]

My apologies, I was too short in my answer. If you read Ilford's documentation about Perceptol and then compare it to the capacity of Microdol-X you as you show it, you will see that there are no similarities. Also in general, looking at a developer A can't give you specific info about a developer B. Until now we can't come to any conclusions about the capacity of Perceptol when used one-shot, hence an attempt to get some more info from Ilford.

let's see what we have:
both developers are of the same type (Metol only, high solvent); published development times are close or identical with most films; capacity per liter (re-use) given is the same for all practical purposes (Perceptol: 4 films per liter; Microdol-X: 16 films per gallon= 3.8 liters). Recommended shelf life is the same. I am not an photochemistry expert but the developers are close enough that a lot of people consider them as clones.

Now Kodak happen to publish some data on their metol only/high solvent developer product that relates to questions people have been looking for here: capacity for diluted developer or instructions for extended development factors in case the minimum volume criteria cannot be met in small tanks. I assume this data is based on actual research and not on speculation. OTOH Harman does not cover any of these questions in their publications. Of course I might be wrong, but it appears to me they simply have not done the necessary tests/research to determine the answer to these very practical questions (else they would be published in the data sheet, wouldn't they?) and I expect that any answer you will get from Harman tech therefore is an (highly) educated guess, no more, no less. I do not think they will start to do a test run in their lab to answer your (or anyone else's for that matter) question. In the worst case, you might even get conflicting answers from Harman tech, depending on who you ask. I am not saying that the Microdol X data points are the definite answer that some are apparently waiting for. I am just saying that in the absence of any definite answer from Harman tech the well founded data for the competitor's product might be helpful to answer some of the questions posed here.

 

[hacked - sepiareverb]

I have always considered Perceptol and Microdol-X to be clones, just as with ID-11 and D-76.

Kodak Tech was (back when they made chemistry and b+w paper) extremely well-informed on everything relating to their products. In the pre-internet days one could call them up and have a conversation that would answer nearly any question. When physical examples were needed they would ask you to mail them in and they would investigate. I certainly trust a Kodak datasheet to be carefully researched.

 

[pentaxuser]

Not "we." Some of us came to a conclusion many, many years ago. And will have no need to knock from within our coffins. If HARMAN doesn't get the answer right 40 years hence, it won't matter. The facts are as they've always been.

I hoped you liked the story. Shades of the macabre mixed with humour to keep the "funny bones" active.

pentaxuuser

 

[john_s]

This reminds me of my kids who say "you can't eat that because its use by date was yesterday." I explain that it doesn't flip over from one state to another at midnight.

In the case of increasing the dilution of developer by reducing the amount of it in, say, 250mL I'm sure that the decline will be gradual, and practically imperceptible until it's clearly inadequate. It will depend, as suggested by some posts above, on the degree of exposure and what sort of contrast the user is looking for. I prefer to use a generous amount of developer to take account of any deterioration caused by its age since mixing and any other vagaries known and unknown. Were I using an expensive developer like DDX I might look at the issue more closely though.

 

[john_s]

.... The answer won't matter; there's too much 'belief' involved.

Well put! It reminds me of lots that's going on at the moment, not just how much Perceptol to use.

 

[howardpan]

This reminds me of my kids who say "you can't eat that because its use by date was yesterday." I explain that it doesn't flip over from one state to another at midnight.

In the case of increasing the dilution of developer by reducing the amount of it in, say, 250mL I'm sure that the decline will be gradual, and practically imperceptible until it's clearly inadequate. It will depend, as suggested by some posts above, on the degree of exposure and what sort of contrast the user is looking for. I prefer to use a generous amount of developer to take account of any deterioration caused by its age since mixing and any other vagaries known and unknown. Were I using an expensive developer like DDX I might look at the issue more closely though.

I’ve seen people say the same thing a number of times. But I wonder if Ilford tests with a standard negative, say one fully exposed frame, to determine if there is enough developer to fully develop the negative to the necessary density. After all, they need to give a recommendation that can handle the worst case scenario, right?

 

[john_s]

I’ve seen people say the same thing a number of times. But I wonder if Ilford tests with a standard negative, say one fully exposed frame, to determine if there is enough developer to fully develop the negative to the necessary density. After all, they need to give a recommendation that can handle the worst case scenario, right?

Surely they would test with the standard 80 square inches of typically fully exposed film developed to a reasonably high contrast?
Would that quantity of developer be the amount beyond which adding more developer would make absolutely no difference at all? Or a very small difference?
Whatever that quantity of developer turns out to be, somewhat less (diluted to cover the film in the tank) would also work (especially for those of us who prefer a slightly lower contrast). And even less would also work especially if you were trying to control excessive contrast by developer exhaustion.

 

[Billy Axeman]

One week ago I mailed Harman Technical Services with a question about the capacity of Perceptol. If they could confirm that 4 films/litre for Perceptol as mentioned in the PDF datasheet is only for reused stock indeed, and when the developer is used as one-shot 1+1 or 1+3 if it would be feasible to use a minimum of 70 ml stock / film (135, 120), as indicated by pentaxuser (OP) in post #1. However, I didn't get an answer, so I guess they prefer the status quo.

 

[twelvetone12]

This is quite interesting, I used perceptol 1+1 in my 300ml tank (so 150ml + 150 water) last year and the results were excellent, with nice dense negatives. I also recall that the box said one can develop up to 10 films with the stock adding 10% time each new film to compensate developer exhaustion (just as is says in the microphen box). I wonder if Ilford had a batch with incorrect information on the box?

 

[Billy Axeman]

This is quite interesting, I used perceptol 1+1 in my 300ml tank (so 150ml + 150 water) last year and the results were excellent, with nice dense negatives. I also recall that the box said one can develop up to 10 films with the stock adding 10% time each new film to compensate developer exhaustion (just as is says in the microphen box). I wonder if Ilford had a batch with incorrect information on the box?

This is info in older boxes, and it is not correct. See my post #3.

Edit - I opened a new box and it still has wrong info (going to 10 films / litre for reused stock) and it contradicts a recent statement from Ilford and the info in the PDF datasheet downloadable from the web site.

 

[twelvetone12]

Just out of curiosity I fished out a very old ILFORD booklet I have (from 1980) and it says that with 1L of solution you can do 5 films, if you use less than 1L, you need to add 10% for each film. So probably the box contains a mix of old and new information. I hope they come back to you...

 

[Billy Axeman]

Just out of curiosity I fished out a very old ILFORD booklet I have (from 1980) and it says that with 1L of solution you can do 5 films, if you use less than 1L, you need to add 10% for each film. So probably the box contains a mix of old and new information. I hope they come back to you...

Yes, that's what you see: 4, 5 or 10 films/litre. These are also the numers you can find in web shops. The most recent correct number is 4 films.

 

[Mick Fagan]

One week ago I mailed Harman Technical Services with a question about the capacity of Perceptol. If they could confirm that 4 films/litre for Perceptol as mentioned in the PDF datasheet is only for reused stock indeed, and when the developer is used as one-shot 1+1 or 1+3 if it would be feasible to use a minimum of 70 ml stock / film (135, 120), as indicated by pentaxuser (OP) in post #1. However, I didn't get an answer, so I guess they prefer the status quo.

I would think that from when you posted a request for information and not having received a reply inside one week, is not an issue. When technical information is requested by a user of a product that one manufactures, then you would not release any information until you are 100% sure that the information you do release, is really correct, is really relevant and is really understandable.

The current wording you have requested clarity over, may be the sticking point in holding back a quick reply.. In situations like this, there is often no quick fix. Any reply, will have to very clearly state the company view of their developer in such a manner that most people can easily understand.

It may be that they are looking at their wording and see an issue, maybe there is no clarity issue in their eyes. But they may see a clarity issue looming after reading your letter, we'll see.

I would think you may need to be a bit more relaxed as to how long a wait is reasonable, before you dismiss their non reply as being a finality.

Mick.

 

[pentaxuser]

Mick, I haven't seen Billy Axeman's e-mail but I can only conclude that if there is a problem for Ilford it centres around the question of whether the 4 films per litre is for re-used stock only. His other question appears to directly reflect the question I asked Ilford in my thread opener and to which it gave the answer that 70mls of stock was based on the minimum required based on a tank holding a minimum of 280mls.

I cannot recall how long it took Ilford to get back to me with a reply but I suspect it was at least a week so maybe workload and the desire to make as clear a statement as possible is accounting for the time. As I assume Ilford keeps an eye on Photrio then it will be aware that this is the subject of a Photrio thread.

pentaxuser

 

[bvy]

One week ago I mailed Harman Technical Services with a question about the capacity of Perceptol. If they could confirm that 4 films/litre for Perceptol as mentioned in the PDF datasheet is only for reused stock indeed, and when the developer is used as one-shot 1+1 or 1+3 if it would be feasible to use a minimum of 70 ml stock / film (135, 120), as indicated by pentaxuser (OP) in post #1. However, I didn't get an answer, so I guess they prefer the status quo.

Did you ever hear anything?

I mixed up some Perceptol this morning. If I could get away with 200ml per 120 film, I could do two at once in my tall stainless steel tank.

 

[Billy Axeman]

Did you ever hear anything?

I mixed up some Perceptol this morning. If I could get away with 200ml per 120 film, I could do two at once in my tall stainless steel tank.

Sorry, no answer from Ilford.

 

[pentaxuser]

Sorry, no answer from Ilford.

I find it hard to believe that Ilford are still composing an answer after this length of time. I suspect that your question has somehow "dropped into a black hole"

I'd remind Ilford of the original question

pentaxuser

 

[MattKing]

Start a conversation here with Harman Tech Service, and reference this thread.

 

[Slixtiesix]

Did you ever hear anything?

I mixed up some Perceptol this morning. If I could get away with 200ml per 120 film, I could do two at once in my tall stainless steel tank.

200 ml is definitely on the safe side. I regularly use 125 ml per one roll of 120 film without a problem.

 

[Billy Axeman]

I find it hard to believe that Ilford are still composing an answer after this length of time. I suspect that your question has somehow "dropped into a black hole"

I'd remind Ilford of the original question

pentaxuser

Well, I'll take the hint from Ilford on this subject and I'm not going to push them any further. Sometimes I also need them for other things and I don't want to be that nagging guy.

I can imagine what they are thinking though. If they confirm that 70 ml stock / film is enough some people here clap their hands for joy and immediately start trying 50 ml of course. The result is probably that the developer isn't what they expected and then abandoned for something else they can dilute more. Also, Ilford is selling less packs when people are milking out the capacity. So, this route leads to all sorts of adverse side-effects for them.

Actually Harman/Ilford has already put a lot of effort in testing their stuff and they have created excellent documentation for it, which is costing them a lot of time and money. So, if you want to deviate from the official advise do your own tests and draw conclusions from that for yourself. That's how I think about it.

 

[bvy]

I agree. Do your own tests. I'm sticking with 250ml for now.

I developed a test roll last night. I forgot how beautiful this developer is. Looks like I can crawl right into my Delta 400 frames.

 

[Billy Axeman]

Yes, recently I also started using Perceptol on HP5+ instead of ID-11 and I am comparing the results (hence my interest in this thread). My photo's look very clean, with mostly architecture as subject.

I'm currently following the standard procedure (UV filter, Perceptol stock, HP5+ @ EI 250, 13 min, 20 C) and I am happy with that: nice density, small grain, good contrast. I'm still not sure about tonality, sometimes it is good, sometimes average.
However, until now I have done only a few films with flat lighting (overcast sky) and I don't know how it looks with more light. I also used two different camera's which isn't good for consistent results.

 

[bvy]

Draw your own conclusions. Right side is the recommended minimum amount of stock for 40in2 of film. The left side is half the recommended amount. Both half sheets were scanned in the same pass with no adjustments.

 

[bascom49]

Draw your own conclusions. Right side is the recommended minimum amount of stock for 40in2 of film. The left side is half the recommended amount. Both half sheets were scanned in the same pass with no adjustments.

View attachment 197531

Nice post. Great to see justification to follow the recommended amount of 250 ml Perceptol.