FB print deterioration: what went wrong here?

koraks · May 23, 2020

kevs said:
Another tip; exhausted rapid fixer looks yellow, like white wine, whereas fresh fixer looks like water.

A little word of warning though: the coloration is due to carry over of developer into the fix, via the stop bath if one is used. If a somewhat longer stop is used (eg one minute) and the stop bath is a colorless type and frequently replaced, even exhausted fixer will be perfectly clear without color. Conversely, if there is a lot of carryover, fixer may become quite yellow quickly, but it may still be perfectly within capacity. Hence, a color indication for exhausted fixer comes with some limitations.

Pat Erson · May 23, 2020

Umberto if you follow Ilford's procedure why don't you use Ilford fixer?

mnemosyne · May 23, 2020

@Umberto
I suggest you read the following article, it is a hands-on guide to pinpointing causes of print deterioration:
Gawain Weaver: A Guide to Gelatin Silver Print Condition and Deterioration
Keep us updated!

markbau · May 23, 2020

Umberto said:
I use Adox Fixer at film strenght 1+4. For this dilution the recommended time for FB paper is 60/80 seconds.

Disagree, I’ve been fixing FB in 1:4 for

Sirius Glass said:
Not enough fixing for FB paper. Think like 10 to 30 minutes, not seconds. When all else fails read the instructions.

10 to 30 minutes in films strength rapid fixer??? No way, you'd never wash it out and you would have image degradation. 2 minutes timed is enough. Read "Mysteries of the Vortex" for the last word on fixing and washing.

Sirius Glass · May 23, 2020

Pat Erson said:
Imho this is far far worse than the 60s time performed by the OP.
And btw 60s at 1+4 is what Ilford recommends as part of their archival process.

"The FB print workflow was the following:
- Dev (factorial development)
- Stop (30 sec.)
- Fixer 1+4 (60 sec.)
- Rinse (5 min.)
- Selenium Toning
- Ilford Washaid (10 min. without agitation)
- Wash (30 min.)"

Umberto I'd tend to think you overused your fixer or used an old one. in any case it's definitely a fixing problem.

It depends on which fixer we are talking about: conventional and rapid fixers, or between Ilford and Kodak, or dilution? See Doremus' posts.

Sirius Glass · May 23, 2020

markbau said:
Disagree, I’ve been fixing FB in 1:4 for

10 to 30 minutes in films strength rapid fixer??? No way, you'd never wash it out and you would have image degradation. 2 minutes timed is enough. Read "Mysteries of the Vortex" for the last word on fixing and washing.

Not rapid fixer, and it was diluted.

Doremus Scudder · May 23, 2020

While all this is interesting, I think we risk confusing the issue (and the OP).

Plus, using really dilute fixer for extended times may be a viable practice, but it's hardly mainstream and may have some problems achieving complete fixation due to the consequences of the weaker dilution. I have experimented with this in the past and wouldn't feel confident recommending it to anyone. I'll stick with the tried-and-true best practices and the manufacturers' recommendations for the most part.

Fixing time has a direct correlation to dilution and type of fixer. Sodium thiosulfate (conventional) fixers take longer than ammonium thiosulfate (rapid) fixers. A higher dilution of either of these requires more time. Longest times would be with diluted conventional fixers. Shortest times with strong rapid fixers. For film, the clearing test will give you a reliable indication of what times you need as well as when the fixer should be discarded. With prints, we need to test and use throughput. It's really that simple.

Choice of fixer type, alkalinity and dilution are a matter of workflow.

@Umberto (and others who might be interested),
It was pointed out to me recently that the Ilford sequence for optimum permanence without toning only calls for a final wash time (after the 10 minutes in the wash aid) of five minutes. The final wash time with toning is 30 minutes. The difference (as was also pointed out to me) was that selenium toner contains ammonium thiosulfate, which soaks into the paper fibers during the toning time. The short wash without toning is based on the short fixing time, which prevents the ammonium thiosulfate and other fixing compounds to soak into the paper base.

The logical conclusion of this is that adding selenium toning to the mix effectively negates the advantage (i.e., the short wash time) that is gained by using strong fixer for a short time. With the toner, one has to wash just as long as with other fixing regimes (e.g., weaker rapid fix for longer times or conventional fixers, which require 5-10 minutes in the fix).

Therefore, there is no reason to use short fixing times with strong rapid fixer if the prints are to be selenium toned other than that the user prefers this. In my opinion, however, the short fixing time is awkward and difficult to achieve in practice, especially with larger prints. Furthermore, the short time almost excludes the two-bath fixing regime for all but the smallest of prints; just try making sure a 16x20-inch print gets exactly 30 seconds each in two baths and has enough time to drain before it hits the water rinse tray on the 60-second mark. Add to this that the one-bath capacity for strong fix at this short time is only about 10 8x10s per liter (which I find wasteful), not to mention what happens when any refixing needs to be done (e.g., after bleaching) and you see why I've opted for the weaker "print-strength" solution of rapid fixer and two-bath fixation.

I primarily use Ilford Rapid Fixer or Hypam, but have used other ammonium thiosulfate based rapid fixers (Kodak, Tetenal, alkaline fixers too) as well in the past. They all work in a similar manner. Ilford lists the 1+9 dilution of their fixers for manual processing of prints. The fixing time is given as two minutes for this dilution. However, this should be viewed as a minimum. Since the paper fibers are going to get saturated with fixer at this time and wash times will need to be appropriately extended, adding a few more seconds doesn't hurt at all; print degradation from fixing too long doesn't start to appear until about 8-10 minutes of total fixing in ammonium thiosulfate fixers.

So, I use "print-strength" fix for 1.5 minutes each in two fixing baths; a total of three minutes. A good 30-40 seconds of this extra minute, however, is drain time. I make sure the print stays immersed and gets agitated for the full 60 seconds (or a bit more) in each bath, then I pick the print up by a corner and let it drain. This can easily take 15-20 seconds, especially for larger prints. I tone, treat in a wash aid and wash for minimum 60 minutes. I test for both residual silver and hypo regularly, so I know this works.

As for testing: for those of us who selenium tone, there's no reason to mix up ST-1. The residual silver test with selenium toner works just as well. Mix a small amount of selenium toner 1+9 (Kodak's recommendation) or stronger (I use 1+4 since I have it on hand; results are the same). Apply a drop of this to the print border or other completely fixed-out areas of a test print and wait 2-3 minutes. Any tint other than a slight (almost unnoticeable) yellow tinge means that the prints are not adequately fixed. These prints should be refixed and your fixing regime adjusted accordingly.

Sorry this got so long, but I hope it helps,

Doremus

Vaughn · May 23, 2020

For the sake of confusion, we should be careful about how speak of 'dilutions'.
Really dilute -- a lot of water
Strong dilution (as in 'strong fix') -- less water
Higher dilution -- more or less water?? A higher concentrated solution, or higher amount of water added?
Diluted -- more water...or drunk

He drank a concentrated concentration of a concoction and got diluted.

Don't mind me...happy hour comes early on Saturdays.

Sirius Glass · May 23, 2020

Sirius Glass said:
Not rapid fixer, and it was diluted.

Doremus Scudder said:
While all this is interesting, I think we risk confusing the issue (and the OP).

Plus, using really dilute fixer for extended times may be a viable practice, but it's hardly mainstream and may have some problems achieving complete fixation due to the consequences of the weaker dilution. I have experimented with this in the past and wouldn't feel confident recommending it to anyone. I'll stick with the tried-and-true best practices and the manufacturers' recommendations for the most part.

Fixing time has a direct correlation to dilution and type of fixer. Sodium thiosulfate (conventional) fixers take longer than ammonium thiosulfate (rapid) fixers. A higher dilution of either of these requires more time. Longest times would be with diluted conventional fixers. Shortest times with strong rapid fixers. For film, the clearing test will give you a reliable indication of what times you need as well as when the fixer should be discarded. With prints, we need to test and use throughput. It's really that simple.

Choice of fixer type, alkalinity and dilution are a matter of workflow.

@Umberto (and others who might be interested),
It was pointed out to me recently that the Ilford sequence for optimum permanence without toning only calls for a final wash time (after the 10 minutes in the wash aid) of five minutes. The final wash time with toning is 30 minutes. The difference (as was also pointed out to me) was that selenium toner contains ammonium thiosulfate, which soaks into the paper fibers during the toning time. The short wash without toning is based on the short fixing time, which prevents the ammonium thiosulfate and other fixing compounds to soak into the paper base.

The logical conclusion of this is that adding selenium toning to the mix effectively negates the advantage (i.e., the short wash time) that is gained by using strong fixer for a short time. With the toner, one has to wash just as long as with other fixing regimes (e.g., weaker rapid fix for longer times or conventional fixers, which require 5-10 minutes in the fix).

Therefore, there is no reason to use short fixing times with strong rapid fixer if the prints are to be selenium toned other than that the user prefers this. In my opinion, however, the short fixing time is awkward and difficult to achieve in practice, especially with larger prints. Furthermore, the short time almost excludes the two-bath fixing regime for all but the smallest of prints; just try making sure a 16x20-inch print gets exactly 30 seconds each in two baths and has enough time to drain before it hits the water rinse tray on the 60-second mark. Add to this that the one-bath capacity for strong fix at this short time is only about 10 8x10s per liter (which I find wasteful), not to mention what happens when any refixing needs to be done (e.g., after bleaching) and you see why I've opted for the weaker "print-strength" solution of rapid fixer and two-bath fixation.

I primarily use Ilford Rapid Fixer or Hypam, but have used other ammonium thiosulfate based rapid fixers (Kodak, Tetenal, alkaline fixers too) as well in the past. They all work in a similar manner. Ilford lists the 1+9 dilution of their fixers for manual processing of prints. The fixing time is given as two minutes for this dilution. However, this should be viewed as a minimum. Since the paper fibers are going to get saturated with fixer at this time and wash times will need to be appropriately extended, adding a few more seconds doesn't hurt at all; print degradation from fixing too long doesn't start to appear until about 8-10 minutes of total fixing in ammonium thiosulfate fixers.

So, I use "print-strength" fix for 1.5 minutes each in two fixing baths; a total of three minutes. A good 30-40 seconds of this extra minute, however, is drain time. I make sure the print stays immersed and gets agitated for the full 60 seconds (or a bit more) in each bath, then I pick the print up by a corner and let it drain. This can easily take 15-20 seconds, especially for larger prints. I tone, treat in a wash aid and wash for minimum 60 minutes. I test for both residual silver and hypo regularly, so I know this works.

As for testing: for those of us who selenium tone, there's no reason to mix up ST-1. The residual silver test with selenium toner works just as well. Mix a small amount of selenium toner 1+9 (Kodak's recommendation) or stronger (I use 1+4 since I have it on hand; results are the same). Apply a drop of this to the print border or other completely fixed-out areas of a test print and wait 2-3 minutes. Any tint other than a slight (almost unnoticeable) yellow tinge means that the prints are not adequately fixed. These prints should be refixed and your fixing regime adjusted accordingly.

Sorry this got so long, but I hope it helps,

Doremus

Just for the record, I follow the mixing instructions and any dilutions of the stock solution as specified by the manufacturer. I figure that if they have already done the R&D, I should listen to them.

Umberto · May 24, 2020

Doremus Scudder said:
So, I use "print-strength" fix for 1.5 minutes each in two fixing baths; a total of three minutes. A good 30-40 seconds of this extra minute, however, is drain time. I make sure the print stays immersed and gets agitated for the full 60 seconds (or a bit more) in each bath, then I pick the print up by a corner and let it drain. This can easily take 15-20 seconds, especially for larger prints. I tone, treat in a wash aid and wash for minimum 60 minutes. I test for both residual silver and hypo regularly, so I know this works.

Doremus, thanks again for you really informative contributions.

I can also use this procedure with Adofix Plus as well as with other rapid fixers based on ammonium thiosulfate, right? In the 1+9 dilution which is the capacity of the first fixer before being replaced? I suppose it's not the same as for the 1+4 dilution, which is 1.5/2.0 square meters for the first bath.

Also, before selenium toning I usually keep the prints in a tray with water without rinsing, then at the end of the session I start toning. In this case which would be the best procedure? As far as I know any print out of the fixer, if kept in water, must be thoroughly washed before selenium. Is it right? Someone recommends a complete archival procedure before toning, others says a 10 minutes wash is sufficient. I am a little bit confused about this point.

Umberto · May 24, 2020

Pat Erson said:
Umberto if you follow Ilford's procedure why don't you use Ilford fixer?

Ilford's procedure is not exclusive, it can be followed with any similar product. Thiosulfate ammonium based rapid fixers are basically the same thing.

Doremus Scudder · May 24, 2020

Umberto said:
Doremus, thanks again for you really informative contributions.

I can also use this procedure with Adofix Plus as well as with other rapid fixers based on ammonium thiosulfate, right? In the 1+9 dilution which is the capacity of the first fixer before being replaced? I suppose it's not the same as for the 1+4 dilution, which is 1.5/2.0 square meters for the first bath.

Also, before selenium toning I usually keep the prints in a tray with water without rinsing, then at the end of the session I start toning. In this case which would be the best procedure? As far as I know any print out of the fixer, if kept in water, must be thoroughly washed before selenium. Is it right? Someone recommends a complete archival procedure before toning, others says a 10 minutes wash is sufficient. I am a little bit confused about this point.

Okay, let's see...

First, I read the directions on Adox Plus fixer and they say a 1+9 dilution is just fine. So go for it.

Second, it's a common misconception that fixer capacity for prints changes with dilution. Somewhat counter-intuitively, it doesn't. What determines when a print fixer needs to be discarded is the concentration of by-products (dissolved silver compounds) in the used fix. After a certain point, the action of the fixer is inhibited by these by-products and stops working efficiently. What changes with the concentration of print fixer is the fixing time. So, the capacity of a print fixer at 1+9 is the same as the 1+4 dilution. The fixing times are just longer. My personal (tested) throughput guideline for Ilford Rapid Fixer and Hypam at the 1+9 dilution is 6 8x10-inch prints per liter of first bath in a two-bath fixing regime. (I like 36 because it's convenient with a 12-slot washer).

About selenium toning: Many people get stains if they hold the prints in water for too-short a time before toning. If you're not getting stains, then everything is fine. If you are, there are two ways to deal with it.

1. wash longer and more thoroughly before toning. This is the best way if you are using a strong or acidic fixer since the acidity of the fixer seems to promote the formation of stains.

2. transfer directly from the second fixing bath to the toner. This works fine if the fixer is not too acidic (and non-hardening). It works for me with my 1+9 dilution of rapid fixers (see below). In either case, the prints need to be well-fixed or an overall yellow stain may result. This latter is really the most important for avoiding stains.

FWIW, here's my work flow: I divide my time into "printing sessions" and "toning sessions." When printing, I work slowly, making adjustments and going through several variations before arriving at a print I deem satisfactory. I develop, stop, give fix 1 (1+9 Rapid Fixer for 1.5-2 minutes), rinse, wash (60 minutes) and dry the prints. These prints are fixed to "commercial standards" or better at this point. Often, I'll end up with only two to six final prints in a printing session (the others end up in the trash). I keep careful count of how many prints have been through the fix and discard the fix before I've reached my 36-8x10s/liter capacity. I'll often go through two or three batches of fixer before I have 32-36 final prints that I want to tone.

For toning, then, I mix up a fresh batch of fixer, which will be fixing bath 2 for all the prints I'm going to tone. I give the prints a 5+-minute water soak, fix in bath 2 for 1.5-2 minutes and transfer the prints directly from the second bath to the selenium toner. After toning, the prints go directly into a tray of wash-aid. Prints get 10 minutes or more in the wash aid and then get transferred directly to the washer (I'll often collect a washer batch in the wash-aid tray before transferring them to the washer). Washing time is again minimum 60 minutes. I test the last print through for residual silver and hypo.

Hope this clears up the confusion,

Doremus

Umberto · May 24, 2020

Doremus Scudder said:
Second, it's a common misconception that fixer capacity for prints changes with dilution. Somewhat counter-intuitively, it doesn't. What determines when a print fixer needs to be discarded is the concentration of by-products (dissolved silver compounds) in the used fix. After a certain point, the action of the fixer is inhibited by these by-products and stops working efficiently. What changes with the concentration of print fixer is the fixing time. So, the capacity of a print fixer at 1+9 is the same as the 1+4 dilution. The fixing times are just longer. My personal (tested) throughput guideline for Ilford Rapid Fixer and Hypam at the 1+9 dilution is 6 8x10-inch prints per liter of first bath in a two-bath fixing regime. (I like 36 because it's convenient with a 12-slot washer).

This is a very interesting clarification, because I've always seen discordant statements by different manufactures. For example, Ilford and Compard declare the same capacity for different dilutions confirming your observations, while Adox not. However, knowing this helps a lot.

Doremus Scudder said:
About selenium toning: Many people get stains if they hold the prints in water for too-short a time before toning. If you're not getting stains, then everything is fine. If you are, there are two ways to deal with it.

1. wash longer and more thoroughly before toning. This is the best way if you are using a strong or acidic fixer since the acidity of the fixer seems to promote the formation of stains.

2. transfer directly from the second fixing bath to the toner. This works fine if the fixer is not too acidic (and non-hardening). It works for me with my 1+9 dilution of rapid fixers (see below). In either case, the prints need to be well-fixed or an overall yellow stain may result. This latter is really the most important for avoiding stains.

In the past I've had some episodes of edge staining after toning prints which were put on hold in a water tray, since then I started to thoroughly wash them before and after toning. Anyway I don't know if it was caused by the holding in water or (more probably at this point) just an insufficient fixing.

Doremus Scudder said:
FWIW, here's my work flow: I divide my time into "printing sessions" and "toning sessions." When printing, I work slowly, making adjustments and going through several variations before arriving at a print I deem satisfactory. I develop, stop, give fix 1 (1+9 Rapid Fixer for 1.5-2 minutes), rinse, wash (60 minutes) and dry the prints. These prints are fixed to "commercial standards" or better at this point. Often, I'll end up with only two to six final prints in a printing session (the others end up in the trash). I keep careful count of how many prints have been through the fix and discard the fix before I've reached my 36-8x10s/liter capacity. I'll often go through two or three batches of fixer before I have 32-36 final prints that I want to tone.

For toning, then, I mix up a fresh batch of fixer, which will be fixing bath 2 for all the prints I'm going to tone. I give the prints a 5+-minute water soak, fix in bath 2 for 1.5-2 minutes and transfer the prints directly from the second bath to the selenium toner. After toning, the prints go directly into a tray of wash-aid. Prints get 10 minutes or more in the wash aid and then get transferred directly to the washer (I'll often collect a washer batch in the wash-aid tray before transferring them to the washer). Washing time is again minimum 60 minutes. I test the last print through for residual silver and hypo.

Interesting to read this since I also frequently separate sessions into printing or toning. I will adopt this modus operandi, finding my throughput testing with ST-1 and HT-2. However in the case of a session "printing+toning", what if I put the prints in a water tray after the first fix, then I go for the second and the subsequent toning and washing? Could be safe?

M Carter · May 24, 2020

I caught only one incidence of the word "testing" here (using selenium to check for residual silver on the border). That's good to do, and I keep straight selenium in a nail polish bottle with the little brush in the lid (new, empty vs. used - they sell empty ones for people that mix their own nail colors). Really handy for testing the border since a tiny brush is right in the lid.

I also do 2-bath fixing for prints, and I test the fresh (2nd) bath at the start of a session; I cut a strip of the same paper I'll be using, and mark 4 lines on it, giving me 5 spaces about an inch each. Under safelight, I fix for 15, 30, 45 and 60 seconds by dipping it deeper into the fix. Give it a good rinse, room lights come on, and into the paper developer. If I see any yellowing around 30-45 seconds, that fixer moves to bath one, and a fresh batch becomes bath 2. The end of the test strip - where I held it in the fix - should turn full black, so I'm also testing my developer (I use Liquidol, which can last weeks bottled properly, so it's important to test it).

I also use residual hypo test on every print that I intend to keep or sell. (I can spend days dialing in a print and masks, and those are usually 8x10 or 11x14, before moving up to 16x20 and up - those days I don't get as intense about testing fixing and washing since most of those sheets will be trashed, but when I move to fulls size, I test pretty religiously).

iakustov · May 25, 2020

Doremus Scudder said:
If you use one-bath fixing, the capacity for optimum permanence is only about 10 8x10s per liter.

Ilford recommend maximum 40 8x10 FB prints per litre of Rapid Fixer. 10 sounds too strict, but I suppose it also depends on how your prints look like, e.g. if there are mostly white than the fixer solution must be deteriorating faster.

miha · May 25, 2020

Umberto said:
Ilford's procedure is not exclusive, it can be followed with any similar product. Thiosulfate ammonium based rapid fixers are basically the same thing.

Not necessary. See this thread: https://www.photrio.com/forum/threads/adox-adofix-a-rapid-fixer.164519/

Doremus Scudder · May 25, 2020

iakustov said:
Ilford recommend maximum 40 8x10 FB prints per litre of Rapid Fixer. 10 sounds too strict, but I suppose it also depends on how your prints look like, e.g. if there are mostly white than the fixer solution must be deteriorating faster.

Unfortunately, Ilford's recommendations are a bit confusing (misleading?). The 40-8x10s-per-liter recommendation is for "commercial use." Read the tech sheet on Rapid Fixer or Hypam more carefully, and in the section entitled, "Silver concentration" and you'll find the following (emphasis added):

"If a high level of image permanence is required for commercial use the silver concentration in the fixer should be kept below 2 g/l when fixing FB papers. This approximates to 40, 20.3 x 25.4 cm, (8 x 10 inch) FB prints. Above this level compounds may remain in the paper base after washing and over time possibly contribute to print staining. For prints that need maximum stability for long term storage a the maximum silver level in the fixer should not rise above 0.5 g/l i.e.. approximately 10 20.3 x 25.4cm (8 x 10in) prints."

They then go on to describe testing with the HT-2 test. Two-bath fixing is mentioned earlier. I prefer to fix to the higher standard.

Doremus

Doremus Scudder · May 25, 2020

Umberto said:
... Interesting to read this since I also frequently separate sessions into printing or toning. I will adopt this modus operandi, finding my throughput testing with ST-1 and HT-2. However in the case of a session "printing+toning", what if I put the prints in a water tray after the first fix, then I go for the second and the subsequent toning and washing? Could be safe?

That should be just fine. One wants to minimize wet time to a certain degree, but holding prints in water for a few hours shouldn't be too bad. It will likely leach out much of the optical brighteners in the paper. I wash longer just to get rid of more of these as well. I don't like the look or the idea of having brighteners in the paper; I think it looks unnatural.

Best,

Doremus

Vaughn · May 25, 2020

Doremus Scudder said:
...It will likely leach out much of the optical brighteners in the paper. I wash longer just to get rid of more of these as well. I don't like the look or the idea of having brighteners in the paper; I think it looks unnatural....Doremus

I remember a conversation with I believe John Sexton a few decades ago (at a FoP workshop) -- he and some other photographers were talking to an Ilford rep. The gist of the conversation was that the rep was surprised about the complaints about the brighteners washing out because the paper isn't wet long enough for them to wash out. He was set straight... I don't know if the situation changed.

Doremus Scudder · May 25, 2020

Vaughn said:
I remember a conversation with I believe John Sexton a few decades ago (at a FoP workshop) -- he and some other photographers were talking to an Ilford rep. The gist of the conversation was that the rep was surprised about the complaints about the brighteners washing out because the paper isn't wet long enough for them to wash out. He was set straight... I don't know if the situation changed.

Some time ago I read (here maybe?) a comment with a graph on how fast the optical whiteners washed out. The upshot of that was that after an hour of washing, most of the whiteners were gone. My library indicates that brighteners loose their effectiveness after a relatively short time when the print is displayed anyway.

Doremus

iakustov · May 26, 2020

Doremus Scudder said:
Unfortunately, Ilford's recommendations are a bit confusing (misleading?). The 40-8x10s-per-liter recommendation is for "commercial use." Read the tech sheet on Rapid Fixer or Hypam more carefully, and in the section entitled, "Silver concentration" and you'll find the following (emphasis added):

"If a high level of image permanence is required for commercial use the silver concentration in the fixer should be kept below 2 g/l when fixing FB papers. This approximates to 40, 20.3 x 25.4 cm, (8 x 10 inch) FB prints. Above this level compounds may remain in the paper base after washing and over time possibly contribute to print staining. For prints that need maximum stability for long term storage a the maximum silver level in the fixer should not rise above 0.5 g/l i.e.. approximately 10 20.3 x 25.4cm (8 x 10in) prints."

They then go on to describe testing with the HT-2 test. Two-bath fixing is mentioned earlier. I prefer to fix to the higher standard.

Doremus

My bad, thanks.
Personally I have set a higher threshold of 20-8x10 per litre FB prints. And I always tone Ilford MGFB Classic paper in Selenium toner to get rid of greenish tint. It must be asked numerous times here, but if there is no stain after selenium toner, is there still a chance that the print will get stained in the future due to inadequate fixing? As I understand selenium fixer converts only metallic silver into selenide and any by-products left after hyposulphite reaction should result in stain..

miha · May 26, 2020

Doremus Scudder said:
SNIP: For prints that need maximum stability for long term storage a the maximum silver level in the fixer should not rise above 0.5 g/l i.e.. approximately 10 20.3 x 25.4cm (8 x 10in) prints."

They then go on to describe testing with the HT-2 test. Two-bath fixing is mentioned earlier. I prefer to fix to the higher standard.

Doremus

True indeed, however this is only relevant when a single fixing bath and no Washaid is used. With addition of the second fixing bath OR Washaid the maximum silver level can be increased to 2 g/l for maximum stability as explained under PRINCIPLES OF GOOD FIXATION, page 3 of the same document.

Doremus Scudder · May 26, 2020

miha said:
True indeed, however this is only relevant when a single fixing bath and no Washaid is used. With addition of the second fixing bath OR Washaid the maximum silver level can be increased to 2 g/l for maximum stability as explained under PRINCIPLES OF GOOD FIXATION, page 3 of the same document.

Two-bath fixing does indeed do the job. That's precisely why I use it. However, the second bath always has very little dissolved silver in it.

I've just read the section on fixation that your refer to (in the Processing B&W Paper tech sheet). Ilford does state that the capacity of a single bath can be increased fourfold by simply using wash aid. This would seem to imply that the wash aid is doing some of the fixing somehow. I haven't studied this thoroughly, just read a lot, but I would tend to question that assumption.

Wash aid, which is really just sodium sulfite and a pH adjuster like bisulfite, can't turn insoluble argentothiosulfates that haven't been completely through the fixation process into soluble ones as far as I know. I'm not sure what Ilford thinks happens by using wash aid that would make the difference.

I've always learned that the build up of dissolved silver in the fixing bath leaves more and more insoluble silver compounds in the emulsion after the level reaches a certain point. A certain amount are "acceptable" for "commercial purposes," but for optimum permanence very few need to remain behind. Therefore, whatever the final fixing bath is for prints processed for optimum permanence need to have a very low level of dissolved silver (Ilford likes 0.5g/liter, Haist mentions 0.2g/liter or less in his work). AFAIK; wash aid helps with replacing the soluble argentothiosulfates by ion exchange and speeding up washing, but isn't a substitute for adequate fixation. Maybe Ilford has some research to the contrary, which I'd love to see. Maybe I'm wrong here, but until I hear from a research chemist that sulfite can somehow complete fixing, I'm going to stick with two-bath fixing, a low throughput and a wash-aid.

These are the times we really miss P.E. Maybe someone with more knowledge than I of the subject would like to comment here?

Best,

Doremus

Umberto · May 26, 2020

Doremus Scudder said:
Wash aid, which is really just sodium sulfite and a pH adjuster like bisulfite, can't turn insoluble argentothiosulfates that haven't been completely through the fixation process into soluble ones as far as I know. I'm not sure what Ilford thinks happens by using wash aid that would make the difference.

True indeed. I don't know the specific formulation of Ilford Washaid, but I think it's not that far from the classic HCA formula essentially based in sodium sulphite.
However I tend to be skeptic about this: the Ilford's document "Processing B&W Paper" which Miha refers to is dated 2001, while in the last Rapid Fixer data sheet from 2010 there isn't anymore any reference about this method. Who knows.

spijker · May 26, 2020

Ilford writes in the technical information sheet of Rapid fix (page 4):
"If a high level of image permanence is required for commercial use the silver concentration in the fixer should be kept below 2 g/l when fixing FB papers. This approximates to 40, 20.3 x 25.4 cm, (8 x 10 inch) FB prints. Above this level compounds may remain in the paper base after washing and over time possibly contribute to print staining."
and at the bottom of the same page;
"The level of silver in a film fixing bath can be allowed to rise to 8–10 g/l without serious effect."
"RC papers can be processed in fixers containing higher levels of silver, 4–6 g/l as the paper base is protected on both sides by an impervious polythene coating."

The way I interpret all this is that it's less about the fixing itself but more about the washing afterwards. When the silver concentration gets too high, the fixer doesn't get washed from the paper properly anymore. Film and RC paper are much less affected as they don't absorb as much fixer as FB paper. That's where the wash aid might come to the rescue and enable sufficient washing anyway for FB paper.

Personally I use a single Ilford Rapid fix bath at 1+4 strength, 1 min fixing time and replenish it with 0.5 l fresh 1+4 fix every 10 sheets of 11x14 inch FB paper. 10 x 11x14 inch = 1 m2. I use sodium sulphite wash aid. So far that's seems to work for me.

FB print deterioration: what went wrong here?

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