Over fixing the negatives

milosz · Dec 10, 2009

Is fixing the negative for say twice the recommended time likely to cause any measurable damage to it? To put it into a real example's context let's say 10 minutes in Ilford Rapid 1:4. Thiosulphates are said to be a rather weak, but still, solvent of metallic silver. Would there be consequences/adverse effects? For example, is extending the fixing time likely to result in any practical loss of density in higher values and so in reduction of negatives dynamic range? Would such time extension have any bearing on washing?

Steve Smith · Dec 10, 2009

No problem.

A general rule of thumb is to fix for twice the clearing time which is effectively double the required time anyway.

If you were leaving them in the fixer for a few days, you may see some problems though.

Steve.

fschifano · Dec 10, 2009

Short answer is no. At least I haven't been able to detect any difference by eye or by the way the negatives print. I think it would take a lot longer than that for there to be any noticeable difference. As for washing times, I can't see where there would be a problem. Long before fixation is complete, fixer had been thoroughly absorbed into the gelatin anyway. The support, of course, absorbs nothing. Keeping fixing times as short as possible is really only an issue with fiber based papers. The idea is to limit the amount of fixer that gets trapped between the fibers of the paper, making washing more difficult.

Anscojohn · Dec 10, 2009

Milosz,
I have heard it said that overfixing prints can, indeed, bleach delicate highlights. I have not, however, heard that this is a problem with negatives. And I do not know why.

Ian Grant · Dec 10, 2009

Chloro-Bromide papers are far more prone to image bleach than Bromide papers or film, with a Rapid fixer it can begin to happen within 3 or 4 minutes if the fixer is very fresh. Films are Bromo-iodide emulsions and much more resilient to fixer bleack. It's also down to grain size the grain in a Warm tone Chloro-bromide emulsion is mych finer, but to slow for camera use. The smaller the grain the easier it is to dissolve.

Ian

BetterSense · Dec 10, 2009

I left an RC print in the fixer overnight. It was totally ruined. I think the film emulsion would be damaged from the extended wet-time before the fixer did any significant bleaching. I sometimes pour fixer in and leave it, and come back 1/2 hour later or something. Never a problem. Especially with tmax.

jeffreyg · Dec 10, 2009

When all else fails, follow directions.

Dave Dawson · Dec 10, 2009

Chop your film in half....Fix one for the recommended time...The other for twice that time....Compare...Then tell us your findings....SORTED.

Cheers Dave

nworth · Dec 10, 2009

With normal fixers and films, twice the recommended time should have no adverse effects. Some powerful fixers, such as xray fixers, could start bleaching the image in that time, and some especially delicate films could be affected. (I don't offhand know any examples, but KB-14 (now KB-25) used to warn people about it.) Rapid fixers are more likely to cause problems than regular fixers.

hoffy · Dec 10, 2009

I have a similar question (but was afraid to ask).

With prints, should I still follow the default "Twice film clearance time" trick? Just to make sure, I fix for way too long (around 90 counted seconds, which is probably closer to 120 seconds, on fixer that takes 40 seconds to clear a neg)

Cheers

Anon Ymous · Dec 11, 2009

Hoffy, the paper manufacturer will provide a reasonable fixing time for the paper and it should be ok for fixer that is withing the useful limits. The 90'', or 120'' isn't excessive*, but I'd advise you to buy some selenium toner to check for proper fixation. Dilution isn't critical, but Kodak proposes diluting 1 part of their Rapid Selenium Toner with 9 parts water. After the print is washed, wipe excess water and place a drop on the margin of the print for 2-3'. You should see no stain, or at most a barely visible stain, otherwise, you should refix the print. You can also use a piece of paper that had been processed just like your print and this test can also be used with FB paper and film. When doing the test on film, cut a clear part of the leader and remember to put the drop on the emulsion side. One more detail though, don't leave the drop on paper/film for ages, it will stain anyway.

* For RC paper.

hoffy · Dec 11, 2009

Thanks for that. I am still playing with RC paper and am pretty sure I am OK. I just don't want to over do it (the losing delicate highlight details thing has me thinking, thats all!!). The other thing is that I get bored when fixing, so the less time the better!

sly · Dec 11, 2009

Yesterday I was rushing to get some negs developed between appointments, planning to leave them washing while I saw my last client of the day. Client arrived 10 minutes early and the negs were left in the fix for 30-40 minutes. Not something to make a habit of, but I don't think it hurt them. Here's a quick neg scan....

RalphLambrecht · Dec 11, 2009

sly said:
Yesterday I was rushing to get some negs developed between appointments, planning to leave them washing while I saw my last client of the day. Client arrived 10 minutes early and the negs were left in the fix for 30-40 minutes. Not something to make a habit of, but I don't think it hurt them. Here's a quick neg scan....

Unfortunately, only a side-by-side comparison would tell.

RalphLambrecht · Dec 11, 2009

milosz said:
Is fixing the negative for say twice the recommended time likely to cause any measurable damage to it? To put it into a real example's context let's say 10 minutes in Ilford Rapid 1:4. Thiosulphates are said to be a rather weak, but still, solvent of metallic silver. Would there be consequences/adverse effects? For example, is extending the fixing time likely to result in any practical loss of density in higher values and so in reduction of negative’s dynamic range? Would such time extension have any bearing on washing?

As Ian already said, it depends on the grain size. I don't think you'll notice a difference with 10 minutes. However, I measured a clear difference at this time with papers. Attached is a test result with Ilford Multigrade IV. These changes are not necessarily visible without a side-by-side comparison, but excessive fixing times will destroy shadow and highlight density in film. Luckily, when it happens, you'll never know what it could have looked like.

Ian Grant · Dec 11, 2009

The degree of loss of detail through over fixing a filmwill also depend on the emulsion type, how fine grain, the developer used because that has a bearing on grain size, the type of fixer etc.

Ralph's comments about Multigrade IV are what I'd expect in a Rapid fixer like Hypam.Ilford Rapid fix etc, but then change to a paper like Polywarmtone, Agfa/Adox MCC, Foma 111 etc (all warm tone) and the same fixer will cause image bleach after 2-3 minutes. I deliberately left a slightly heavy print in some fixer last week to "lighten up" for about 8 minutes - it did and when Selenium Toned is it's not far off a correctly exposed print, shadow separations not quite as good.

Film fixer is used to a higher capacity/silver content than print fixer and if not fresh will be less aggressive in an over fixing situation, but it's still not a good idea.

Ian

BetterSense · Dec 11, 2009

RalphLambrecht said:
Attached is a test result with Ilford Multigrade IV.

If I interpret your graph correctly, the light tones on the print (VII or so) are relatively unaffected by the extended fixing, but the shadow tones (zones II or so) are more effected? This is the opposite of what I would have expected.

RalphLambrecht · Dec 11, 2009

BetterSense said:
If I interpret your graph correctly, the light tones on the print (VII or so) are relatively unaffected by the extended fixing, but the shadow tones (zones II or so) are more effected? This is the opposite of what I would have expected.

Correct. Remember, this was a print test. The highlights have less silver, hence, they got less to loose. Percentage-wise, the loss may be very similar.

nworth · Dec 11, 2009

hoffy said:
I have a similar question (but was afraid to ask).

With prints, should I still follow the default "Twice film clearance time" trick? Just to make sure, I fix for way too long (around 90 counted seconds, which is probably closer to 120 seconds, on fixer that takes 40 seconds to clear a neg)

Cheers

Prints seem to be more sensitive to overfixing than films, but you have to be careful about underfixing as well. With papers, you can't see when the emulsion has cleared. The best policy is to follow the manufacturer's instructions. Most recommend 2 to 4 minutes in rapid fixer. Your situation is more likely to underfix than overfix with the usual fixers.

RalphLambrecht · Dec 12, 2009

nworth said:
Prints seem to be more sensitive to overfixing than films, but you have to be careful about underfixing as well. With papers, you can't see when the emulsion has cleared. The best policy is to follow the manufacturer's instructions. Most recommend 2 to 4 minutes in rapid fixer. Your situation is more likely to underfix than overfix with the usual fixers.

Well said. The biggest processing danger to photographic longevity is underfixing, followed by underwashing and the lack of toning!

polyglot · Dec 12, 2009

Ilford Rapid Fixer says on the bottle 30s for RC and 1min for FB. I recently got a big batch of Kentmere Fineprint FB and it says 5min fix but doesn't say if that's with sodium or ammonium thiosulphate.

What sort of time would be reasonable? If I get it wrong, how long will it take for the prints to visibly degrade?

And washing... usual recommendations are for half an hour. I have a very (decades) experienced-in-printing friend who does a variant of the Ilford wash on FB paper (3 baths, a few mins in each) and reckons that's more than sufficient washing. Since the 3-bath Ilford wash is effective with film, is there any reason why people continue to recommend the hugely-wasteful running water approach for either film or paper?

Ian Grant · Dec 12, 2009

RalphLambrecht said:
Well said. The biggest processing danger to photographic longevity is underfixing, followed by underwashing and the lack of toning!

The second is actually poor fixing in a silver laden fixing bath particularly with fibre based prints, no inrease in fixing time, washing or any type of toning will protect the umage from staining etc ether at the toning stage or over time.

For this reason most photographers use a two bath fixing sequence.

Ian

Anon Ymous · Dec 12, 2009

polyglot said:
Ilford Rapid Fixer says on the bottle 30s for RC and 1min for FB. I recently got a big batch of Kentmere Fineprint FB and it says 5min fix but doesn't say if that's with sodium or ammonium thiosulphate...

Ah, yes! I bought a 1l bottle yesterday and noticed the same thing, but have a closer look and you'll see that this is for the 1+3 dilution, even less diluted than the 1+4 they proposed until now. I also noticed that the ingredients listed on the label have changed somewhat. Older bottles listed sodium acetate, sulfite and bisulfite, ammonium thiosufate and water. The new bottle has acetic acid, sodium sulfite, water, ammonium thiosulfate.

Regarding how much time a print needs in the fixing bath, follow the papers manufacturer's times for paper strength fixer (for a rapid one), but do check with selenium toner to be sure. There's no substitute for real evidence and FB prints can be archival only if they're treated accordingly! In any other case, an RC print will be probably better.

EDIT: Forgot to say that when dealing with FB paper, two bath fixing is the best way.

RalphLambrecht · Dec 12, 2009

Ian Grant said:
The second is actually poor fixing in a silver laden fixing bath particularly with fibre based prints, no inrease in fixing time, washing or any type of toning will protect the umage from staining etc ether at the toning stage or over time.

For this reason most photographers use a two bath fixing sequence.

Ian

Ian

Correct, but for me, that's still in the first category of 'underfixed'!

RalphLambrecht · Dec 12, 2009

polyglot said:
Ilford Rapid Fixer says on the bottle 30s for RC and 1min for FB. I recently got a big batch of Kentmere Fineprint FB and it says 5min fix but doesn't say if that's with sodium or ammonium thiosulphate.

What sort of time would be reasonable? If I get it wrong, how long will it take for the prints to visibly degrade?...

Before this conversation about how long it takes before fixers attack the image is misunderstood: It is actually irrelevant, because if you have your FB print in the fixer long enough for this to happen, your print is lost anyway, because no washing in the world will get the fixer out of the paper fibers again.

polyglot said:
...And washing... usual recommendations are for half an hour. I have a very (decades) experienced-in-printing friend who does a variant of the Ilford wash on FB paper (3 baths, a few mins in each) and reckons that's more than sufficient washing. Since the 3-bath Ilford wash is effective with film, is there any reason why people continue to recommend the hugely-wasteful running water approach for either film or paper?

Again, here are the three main 'secrets' to get print longevity:

1. Fix as much as you need but as short as you can to get the non-image silver content below 0.008 g/m^2. (two-bath fixing works best)
2. Wash as long as you need to get below 0.015 g/m^2 of residual thiosulfate. (washing depends on diffusion, constant fresh water works best, because it prevents equilibrium)
3. Tone the print in selenium (or better sulfide) to convert metallic silver into more stable compounds.

There are effective tests to confirm 1 and 2 from whatever method you chose.

Over fixing the negatives

milosz

Steve Smith

fschifano

Anscojohn

Ian Grant

BetterSense

jeffreyg

Dave Dawson

nworth

hoffy

Anon Ymous

hoffy

sly

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BetterSense

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Over fixing the negatives

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