I've been using Ilford Rapid Fixer for some time. I make 500ml of a 1+4 dilution, use it for ten or twelve rolls, discard it and make another batch. I use a 480ml Arista stainless steel tank and two Hewes reels. I use 500ml brown glass bottles and fill the tank directly from them. Information seems to vary. Iffords data sheet list 24 36 exposure rolls per liter of working solution as expected capacity before exhaustion. That's was the basis for fixing twelve rolls before a fresh batch. I don't want to stretch it to exhaustion.
Ilford Rapid Fixer, how many rolls from 500ml
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I use for much more rolls than this. Especially if you use proper stop bath, Ilford Fixer does not get exhaust at all, at least not in my experience.
You can always test the fixer before using it, then multiply that number by 2, that will be safe
You can always test the fixer before using it, then multiply that number by 2, that will be safe
The caracity figure does have some safety margin, but between to low cost of fixer and getting a nasty surprise a few years in the future if your usage is too aggressive, It is proably not worth the risk to push very far.
Thanks for the replies. I use a stop bath, mostly to save water.
I waste fixer, I use a Jobo so I have no idea how quick the film clears. Back when I used a good old reliable, inexpensive Paterson tank I fixed with the tank open. It was very obvious when the fixer was tired.
I suppose I should fix off the machine...........
Nah!
I suppose I should fix off the machine...........
Nah!
The only time I get too worried about fixer capacity is when I'm using TMax, then I test the fixer fairly regular. Its not that hard.
Yep, I mostly shoot T-grain or the equivalent. TMax gobbles up fixer, conventional film clears fast and is easier on the fix.
If you don't want to stretch it to exhaustion. go to a two-bath fixing method and you can be sure to never underfix your precious films without wasting a ton of fixer.
I kept my *Rapid Fixer in Jobo's 600ml white bottle. The colour of the fixer can tell me whever it is safe to use.
As far as I could recall , the time I notice the Ilford Rapid Fixer has lost power is when the fixer has lost its colour . The freshly made fixer is having a yellow like colour but after 13-14 rolls of 135 film it has started getting pale , and after that, maybe almost the 20th roll it lost its function. I don't think it could reach 24 rolls .
As far as I could recall , the time I notice the Ilford Rapid Fixer has lost power is when the fixer has lost its colour . The freshly made fixer is having a yellow like colour but after 13-14 rolls of 135 film it has started getting pale , and after that, maybe almost the 20th roll it lost its function. I don't think it could reach 24 rolls .
I have been developing Tri-X in a 1:50 dilution of Rodinal and haven't had any problems with getting clear edges and well defined spacing between the negatives. Today, I tried a couple of test rolls using Ilfotec HC and the film didn't seem to clear as well. I made a fresh batch of Rapid Fixer and I'll try another couple of test rolls. I also labeled the bottle with the date mixed to keep track of the number of rolls.
I followed Ilfords data sheet, making a 1+3 stock solution and then diluting 1+7 for working strength of 1:31. The negatives looked great but they had a bluish tint. Since all the film was exposed within a couple of blocks of my house, it's easy to retrace my steps with some fresh film.
I followed Ilfords data sheet, making a 1+3 stock solution and then diluting 1+7 for working strength of 1:31. The negatives looked great but they had a bluish tint. Since all the film was exposed within a couple of blocks of my house, it's easy to retrace my steps with some fresh film.
I mixed Ilford Rapid Fix last week,1:4.
The instructions stated that life expectancy at 1:4 was something like 4 days.
I find that to be ludicrous....
I processed a sheet of 8x10 yesterday and the film came out fine.
The instructions stated that life expectancy at 1:4 was something like 4 days.
I find that to be ludicrous....
I processed a sheet of 8x10 yesterday and the film came out fine.
I mixed Ilford Rapid Fix last week,1:4.
The instructions stated that life expectancy at 1:4 was something like 4 days.
I find that to be ludicrous....
I processed a sheet of 8x10 yesterday and the film came out fine.
The data sheet for Ilford Rapid Fixer says this:
Unreplenished ILFORD RAPID FIXER working
strength solutions should last for up to:-
6 months in full tightly capped bottles
2 months in a tank or dish/tray with a floating lid
1 month in a half full tightly capped bottle.
7 days in an open dish/tray.
There are two aspects to fixer 'exhaustion'.
The first is actual exhaustion of the thiosulfate. A commercial rapid fixer concentrate will generally be 50-60% ammonium thiosulfate, so 500ml of a 1+3 working stock will contain around 70g of ammonium thiosulfate. Now, let's do a little (haphazard/quick & dirty, paper napkin) calculations on this. B&W film contains up to 5g/m2 of silver, and a single roll is about 0.05m2 and thus would be 0.25g per film. The stoichiometry of fixing works out as around 1:2.5, so fixing 1 mole of silver halide will use around 2.5 moles of thiosulfate. Ammonium thiosulfate is around 148g/mol and silver bromide 188g/mol, so fixing 0.25g of silver bromide, or 1.33mmol AgBr, will require around 3.3mmol or so ammonium thiosulfate, which works out as roughly 0.5g. Since we have 70g of the stuff in our 500ml working strength fixer, you'd expect the capacity to be up to 140 films or so. Note that this is a very rough estimate and that the actual number will be quite a bit off depending on actual silver content of the film, fixing efficiency (i.e. thiosulfate availability), which fixing reactions actually take preference, allowed time to let the reaction complete, etc.
The second part is the silver content of the used fixer solution. Reusing fixer means that silver salts accumulate in the used fixer, and bathing consecutive rolls of film means you're effectively permeating the emulsion on these films with increasingly high concentrations of a silver solution. In principle this is not a problem, provided that these silver salts remain well soluble and sufficient washing follows fixing to remove them. Since a gelatin emulsion on a non-permeable base tends to wash relatively well, this is not a massive issue with film and RC paper, but it's a significant concern with fiber paper. However, even with film, it seems wise to limit how much silver you put into the emulsion (in principle an unnecessary activity, and detrimental to archival stability) as a result of fixer reuse. If you take 4g of silver as a reasonable upper limit of reused fixer for film (for paper, I'd stick to lower figures), this means that around 0.25g per film works out into 16 rolls of film per liter of fixer per liter of used fixer, or 8 rolls for 500ml.
The main takeaway from this, IMO, is that it's possible to make a rough estimate of a fixer's useful capacity, but that this estimate depends greatly on a range of assumptions, which easily tilt the balance significantly in either direction. Simply put: it's a good deal of guesswork and it's impossible to give hard and fast numbers. Fixer as such as a vast capacity, but the limits are posed mostly by how much silver you allow to accumulate in it before discarding, fixing speed (which tends to go down as the fixer is reused) etc.
What I've not addressed above is the problem of keeping jars of used fixer around and what that may do to your film. Everyone who has forgotten about a bottle of used fixer for a month or two knows that the silver will tend to plate out on the walls of the bottle and/or precipitate as tiny black particles. When reusing fixer that is in the process of doing so, these silver particles and flakes can easily embed themselves inside the emulsion and they prove to be very hard (or even impossible) to wash out once they're lodged in the gelatin. The net result is a firmament of white specks that will end up in every print or scan. It's crucial to only re-use fixer as long as it has not started to precipitate out sold particles.
Personally, I'd place the limit at 6-8 rolls per 500ml of 1+3 working solution when reusing fixer, and not keep used fixer around for more than maybe a week or two, depending on conditions (ah, more assumptions...). Although in my own use, I actually tend to mix film fixer at around 1+10 instead and mostly use it one shot, in a rotary setup for 135 and 120 films. This eliminates virtually all of the issues mentioned, and given the relatively low cost of fixer, it's not an expensive insurance against problems, either.
As anything in photography, seemingly simple things can be made very complicated. I think the trick is to simplify them again, in the end, and in this case, I do this by using film fixer one shot. It frees up mental capacity and shelf space for more important things.
Edit: corrected a pretty massive error in the capacity calculations; thanks @Raghu Kuvempunagar for catching that one!
The first is actual exhaustion of the thiosulfate. A commercial rapid fixer concentrate will generally be 50-60% ammonium thiosulfate, so 500ml of a 1+3 working stock will contain around 70g of ammonium thiosulfate. Now, let's do a little (haphazard/quick & dirty, paper napkin) calculations on this. B&W film contains up to 5g/m2 of silver, and a single roll is about 0.05m2 and thus would be 0.25g per film. The stoichiometry of fixing works out as around 1:2.5, so fixing 1 mole of silver halide will use around 2.5 moles of thiosulfate. Ammonium thiosulfate is around 148g/mol and silver bromide 188g/mol, so fixing 0.25g of silver bromide, or 1.33mmol AgBr, will require around 3.3mmol or so ammonium thiosulfate, which works out as roughly 0.5g. Since we have 70g of the stuff in our 500ml working strength fixer, you'd expect the capacity to be up to 140 films or so. Note that this is a very rough estimate and that the actual number will be quite a bit off depending on actual silver content of the film, fixing efficiency (i.e. thiosulfate availability), which fixing reactions actually take preference, allowed time to let the reaction complete, etc.
The second part is the silver content of the used fixer solution. Reusing fixer means that silver salts accumulate in the used fixer, and bathing consecutive rolls of film means you're effectively permeating the emulsion on these films with increasingly high concentrations of a silver solution. In principle this is not a problem, provided that these silver salts remain well soluble and sufficient washing follows fixing to remove them. Since a gelatin emulsion on a non-permeable base tends to wash relatively well, this is not a massive issue with film and RC paper, but it's a significant concern with fiber paper. However, even with film, it seems wise to limit how much silver you put into the emulsion (in principle an unnecessary activity, and detrimental to archival stability) as a result of fixer reuse. If you take 4g of silver as a reasonable upper limit of reused fixer for film (for paper, I'd stick to lower figures), this means that around 0.25g per film works out into 16 rolls of film per liter of fixer per liter of used fixer, or 8 rolls for 500ml.
The main takeaway from this, IMO, is that it's possible to make a rough estimate of a fixer's useful capacity, but that this estimate depends greatly on a range of assumptions, which easily tilt the balance significantly in either direction. Simply put: it's a good deal of guesswork and it's impossible to give hard and fast numbers. Fixer as such as a vast capacity, but the limits are posed mostly by how much silver you allow to accumulate in it before discarding, fixing speed (which tends to go down as the fixer is reused) etc.
What I've not addressed above is the problem of keeping jars of used fixer around and what that may do to your film. Everyone who has forgotten about a bottle of used fixer for a month or two knows that the silver will tend to plate out on the walls of the bottle and/or precipitate as tiny black particles. When reusing fixer that is in the process of doing so, these silver particles and flakes can easily embed themselves inside the emulsion and they prove to be very hard (or even impossible) to wash out once they're lodged in the gelatin. The net result is a firmament of white specks that will end up in every print or scan. It's crucial to only re-use fixer as long as it has not started to precipitate out sold particles.
Personally, I'd place the limit at 6-8 rolls per 500ml of 1+3 working solution when reusing fixer, and not keep used fixer around for more than maybe a week or two, depending on conditions (ah, more assumptions...). Although in my own use, I actually tend to mix film fixer at around 1+10 instead and mostly use it one shot, in a rotary setup for 135 and 120 films. This eliminates virtually all of the issues mentioned, and given the relatively low cost of fixer, it's not an expensive insurance against problems, either.
As anything in photography, seemingly simple things can be made very complicated. I think the trick is to simplify them again, in the end, and in this case, I do this by using film fixer one shot. It frees up mental capacity and shelf space for more important things.
Edit: corrected a pretty massive error in the capacity calculations; thanks @Raghu Kuvempunagar for catching that one!
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There extst very simplistic "fixer control strips" from old times, which measure fixer pH. Back then fixer was acidic and stop bathes were not ubiquitous, so if you carried enough (alkaline) developer into fixer, these "fixer control strips" would report this higher pH as "change your fixer".
This method obviously won't work, if you use an acidic stop bath. In fact, these "fixer control strips" would even report even silver nitrate solution as "fixer still good".
Please don't put any faith into these "fixer control strips" based on pH. And please don't use your fixer longer than what the bottle says.
Just to avoid confusion, I’ve meant film clearing time, described by Ilford Rapid Fixer Manual and again as stated by the same manual, using stop bath prolongs the life. Before I start any session, I always check film clearing time, it is a fool proof method to see the activity of fixer.
If we read the same manual, it also says Stop bath is good for only 15 rolls, now that’s completely out of my observation. As the bath has a dye, we know when it exhausts and it is way beyond 15 rolls.
I dont know if we can ever conclude that based on the same manual, the stop bath should exhausts before fixer (15 vs 24) so it is good to use fixer until stop bath exhausts but I personally think, checking it before every session based on film clearing time is a good method.
If we read the same manual, it also says Stop bath is good for only 15 rolls, now that’s completely out of my observation. As the bath has a dye, we know when it exhausts and it is way beyond 15 rolls.
I dont know if we can ever conclude that based on the same manual, the stop bath should exhausts before fixer (15 vs 24) so it is good to use fixer until stop bath exhausts but I personally think, checking it before every session based on film clearing time is a good method.
This very elegant calculation leaves out a few very important factors, which drastically reduce effective fixer capacity:
- The balance between AgBr and these Silver Thiosulfate complexes is not as strong towards the complexes as it should be. You need quite some surplus of thiosulfate to fix AgBr to archival standards, and with AgI this required surplus is yet higher.
- Film emulsions had a tendency towards high iodide in the last decades, because it increases film sensitivity. Therefore many old capacity number are bound to break down with new materials.
- While many chemical reactions are considered "complete", when 90% of the reactants have done their job, we need an extremely high ratio of reacted vs. unreacted AgBr. Compare the silver amount you mentioned for fresh film with limit amounts for archival stability.
- Since the 50ies or 60ies commercial makers had access to X ray analysis for retained silver. They know perfectly well, where acceptable levels of retained silver would be, and how strong fixer had to be to reach that. Their stated numbers carry a lot more weight than anecdotal evidence or ballpark calculations presented here.
- If we bring wet film into fixer, we do not only bring in silver ions: we bring in bromide ions, which tilt the balance back towards AgBr, and we also bring in carry over water, which dilutes our fixer. With a Jobo 1510 tank I once measured carry over liquid to be 10-15ml depending on how long I drained. These 10-15ml were measured without the film spools and without film! If you reuse some liquid 5 or more times, I would expect a sizable amount of it lost through carryover to the next bath, and replaced with whatever you used before that bath. Even if this 140 rolls/liter calculation held in practice, you could process a lot fewer rolls once you account for carry over.
Stop bath capacity depends strongly on which developer you use or better: how alkaline and how concentrated it is. Crawley's FX-11 will put a lot more load on your stop bath than Rodinal 1:200. The 15 rolls/liter number you found probably tries to cover all bases, so I am not surprised that you reach much higher capacities in your setup.
Yes that might be the reason because I use pretty much only Rodinal and usually at 1+50. Very recently I’ve done some tray stop bath while creating unsharp masks and they have exhausted much much quicker than when I’ve used with Rodinal.
On the other hand, I could just follow the directions in the technical datasheets. I don't mind giving Kodak and Ilford scientists the benefit of the doubt.
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MattKing
Moderator
+1
Here is what the datasheet says:
That suggests that the answer is 12 rolls.
The T-grain/Delta films are more demanding, so 12 may be high.
I test my fixer's remaining capacity regularly, using a clip test.
Here is how to do clip tests: https://www.photrio.com/forum/resou...ixing-procedure-for-black-white-negatives.75/
Went out this morning a put two rolls of Tri-X at ISO 320 through the M4-2. I'll follow Ilfords developing instructions, fresh Rapid Fixer for 5-6 minutes. Normally, I do a modified Ilford water saving wash but today I'll put the tank under running water for ten minutes and see if that clears the blue tint. I'll post some later. Thanks for the help!
Do read the data sheet. It's here: https://assets.website-files.com/5b...3a2b1b17efb_tech specs ilford rapid fixer.pdf
If you don't want to do your own tests, follow the instructions. Err on the side of underusing your fixer if anything.
Fixing is a complex chain of reactions and fixer capacity is affected by a number of things. Whether you're fixing film, RC or fiber-base paper makes a difference as well. It's interesting and rewarding to learn about all this, but trust those with the PhDs in chemistry and the research background unless you're willing to go down the rabbit hole yourself.
Ilford's tech pub gives you all you need to know to do it right.
Oh, and do follow the link MattKing gives you above to learn about the clearing test.
Best,
Doremus
If you don't want to do your own tests, follow the instructions. Err on the side of underusing your fixer if anything.
Fixing is a complex chain of reactions and fixer capacity is affected by a number of things. Whether you're fixing film, RC or fiber-base paper makes a difference as well. It's interesting and rewarding to learn about all this, but trust those with the PhDs in chemistry and the research background unless you're willing to go down the rabbit hole yourself.
Ilford's tech pub gives you all you need to know to do it right.
Oh, and do follow the link MattKing gives you above to learn about the clearing test.
Best,
Doremus
I am familiar with the datasheets. I don't follow them. I use all my chemicals one shot.
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