Rapid Fixer Use

[Bobby Brewster]

Hi,

I have just mixed up 1L of Ilford Rapid Fix at 1:4 dilution. I will only be using this to fix film. On refection, I probably should only have mixed 500ml but I haven't so here I am.

Anyway, given my error, would it be best to split this 1:4 solution into two 500ml bottles and use one at a time or use 500ml of my current solution to fix a film and then return to the large bottle of 1:4 solution and continue this procedure, testing the fixer on a film leader when I use it?

I imagine both would work, but I am wondering what the most sensible would be with due regard to the shelf - life of the mixed solution and the pros and cons of returning the used quantity fixer to the main ( mixed ) 1L of solution

 

[loccdor]

It likely won't matter, if you use 500ml amounts of chemicals you probably don't shoot enough film to exhaust the fixer. But 500ml containers are a little easier to lift.

I have my fixer in a gallon (~4L) jug and mix up a new one every year. I've never had any of the fixers I've tried fail or even lose much strength, but the silver that floats around in them can get annoying and I'd rather make a new batch than try to filter it. I'm processing 40-80 B&W films per year.

 

[MattKing]

Leave it in the 1 litre bottle and pour the used fixer back into the bottle after each use.
You will enjoy similar longevity, and avoid the hassle and potential confusion of the extra bottle.
Do two things to track the capacity:
1) track the number of rolls you use the fixer for. I put painter's tape on my fixer bottle, and mark it with a hash/tally mark each time a roll goes through - like this:

The data sheet for the fixer will give you recommendations for capacity: and
2) Record the clearing time when you have fresh fixer, and then on a regular basis, perform a clip test, and then see how over time the clearing time changes. Some suggest that if the clearing time increases by 50%, it is time to consider replacing it.
Here is a link to how to perform a clip test to check clearing time - plus an additional wrinkle that works for me, but most don't bother with: https://www.photrio.com/forum/resou...ixing-procedure-for-black-white-negatives.75/

 

[Doremus Scudder]

Read this: https://www.ilfordphoto.com/amfile/file/download/file/1833/product/711/

Doremus

{Moderator edit: direct link substituted for Google search result}

 

[Donald Qualls]

Some suggest that if the clearing time increases by 50%, it is time to consider replacing it.

I've always heard that as clearing time doubling being the exhaustion point. A 50% increase would be a very conservative capacity, especially for rapid fixer.

 

[mshchem]

Leave it in the 1 litre bottle and pour the used fixer back into the bottle after each use.
You will enjoy similar longevity, and avoid the hassle and potential confusion of the extra bottle.
Do two things to track the capacity:
1) track the number of rolls you use the fixer for. I put painter's tape on my fixer bottle, and mark it with a hash/tally mark each time a roll goes through - like this:
View attachment 383945
The data sheet for the fixer will give you recommendations for capacity: and
2) Record the clearing time when you have fresh fixer, and then on a regular basis, perform a clip test, and then see how over time the clearing time changes. Some suggest that if the clearing time increases by 50%, it is time to consider replacing it.
Here is a link to how to perform a clip test to check clearing time - plus an additional wrinkle that works for me, but most don't bother with: https://www.photrio.com/forum/resou...ixing-procedure-for-black-white-negatives.75/

+1!!!

 

[mshchem]

 

[mshchem]

So using Kodak's rapid fix film strength you should (in theory) get 30 36 exposure rolls per quart (946mL)

 

[MattKing]

So using Kodak's rapid fix film strength you should (in theory) get 30 36 exposure rolls per quart (946mL)

Or using the Ilford Datasheet linked to above, and 1+4 strength, twenty-four 135-36 rolls per litre.
The Ilford Datasheet is a tad more recent than the Kodak Darkroom Dataguide shared by @mshchem .

 

[blee1996]

Or using the Ilford Datasheet linked to above, and 1+4 strength, twenty-four 135-36 rolls per litre.
The Ilford Datasheet is a tad more recent than the Kodak Darkroom Dataguide shared by @mshchem .

I confirm that the Ilford fixer capacity is quite safe, based on my experience.

 

[250swb]

It won't matter, just test on a film leader every now and again to see how long a drop of fix takes to clear the emulsion, then double it.

 

[mshchem]

Or using the Ilford Datasheet linked to above, and 1+4 strength, twenty-four 135-36 rolls per litre.
The Ilford Datasheet is a tad more recent than the Kodak Darkroom Dataguide shared by @mshchem .

Also this 1970 dataguide pre-dates tabular film. T-Max eats up fixer.

 

[Bobby Brewster]

Thank you for your help. This is what I needed to know

 

[RalphLambrecht]

Hi,

I have just mixed up 1L of Ilford Rapid Fix at 1:4 dilution. I will only be using this to fix the film. On refection, I probably should only have mixed 500ml but I haven't so here I am.

Anyway, given my error, would it be best to split this 1:4 solution into two 500ml bottles and use one at a time or use 500ml of my current solution to fix a film and then return to the large bottle of 1:4 solution and continue this procedure, testing the fixer on a film leader when I use it?

I imagine both would work, but I am wondering what the most sensible would be with due regard to the shelf - life of the mixed solution and the pros and cons of returning the used quantity fixer to the main ( mixed ) 1L of solution

The most frequent processing error is underfixing. The best fixing method is two-bath fixing, where an already used but not exhausted fixer is used first, followed by a fresh fixing bath, which then is demoted to be the first fixing bath, and so on. I would start with two fresh fixing baths for the first film. Then, use the 2nd fixer as the first fixer for the second film, followed by a fresh bath again. Then continue this way until all fixer is used up. To be super archival, monitor the silver content of the first fixer and make sure it never exceeds 1 g silver per liter.

 

[Doremus Scudder]

For using rapid fixers on film. Do a clearing test with the film(s) you use with freshly-mixed fixer to establish a baseline.

To determine fixing time for a specific batch in used fixer either:

~ Do a clearing test on the film immediately before fixing and fix the film for a minimum of twice the clearing time. Note that the clearing time will increase as the fixer is used or degrades due to age. When the clearing time in the used fixer reaches twice that in fresh fixer, the fixer is no longer good and should be replaced.

... or:

~ Fix all your films for a minimum of 4x the clearing time in fresh fixer. This is the time needed for the last films through the fixer just as it reaches exhaustion. The earlier films get more fixing time, but this makes zero difference with film. This eliminates the need to do the clearing test before each batch. You do, however, have to keep an eye on throughput and test the fixer for exhaustion as it approaches the end of its capacity. So, do clearing tests to determine when to discard the fixer and mix fresh before your throughput reaches the manufacturers' published capacity, or earlier if the fixer has been stored for a longer period.

This, IM-HO is best practice for small darkrooms without access to lab monitoring equipment.

For RC prints, using throughput as a guide is more practical, since a clearing test is more complicated. The trick is to test for residual silver (inadequate fixing) when the manufacturers' throughput capacity is being approached. More below.

For fiber-base papers, two-bath fixation is recommended to extend the capacity of the fixer. One- bath fixation works, but has a rather small throughput capacity if the goal is to fix prints to "optimum permanence" standards. According to Ilford, the capacity for one-bath fixation of fiber-base prints cannot exceed 10 8x10-inch prints per liter if processing for optimum permanence. (Note that for "commercial" or "general-purpose" levels of permanence, the capacity is around 40 8x10-inch prints per liter. Most users of fiber-base paper these days are making art prints and desire the best standard of permanence they can get, though.) The reason for the reduced capacity is that the levels of dissolved silver in a fixing bath for fiber-base prints needs to be lower than that for film or RC paper. If not, the paper base bonds to fixer byproducts and retains these, which then cannot be washed out.

With two-bath fixing, one can process up to 40 8x10-inch prints per liter of bath one, but that is then followed by bath two, which stays relatively fresh and finishes up the rest of the fixation not reached in bath one. After the capacity for bath one has been reached, the first bath is discarded, bath two is promoted to become bath one, and a new bath two is mixed. This can be repeated through 5-7 cycles before both baths need to be mixed fresh.

Testing for adequate fixation is important to determine throughput capacity. One can just use the manufacturers' recommendations, but testing is not difficult. I tested my workflow to find my own general capacity and now just test a print or two toward the end of that throughput.

Tests for residual silver in clear areas of the print (which show if fixation is adequate or not) include the ST-1 test and the selenium toner test. The ST-1 test is good, but requires a separate and fresh test solution of sodium sulfide. I find the selenium toner test more practical, since I always have the toner on hand and it never goes bad. In both cases, one simply puts a drop of the test solution onto an unexposed portion of a processed print (or an unexposed test strip processed just for testing purposes). The drop is rinsed off after three minutes; any stain other than a very faint yellowing indicates inadequate fixation. Search here for specifics on the tests.

Best,

Doremus


I find the selenium toner test to be more practical and just as