Why Two-Bath Fix?

[nihraguk]

Hi everyone,

I've tried searching for an explanation on this topic, but still have some queries I'd like to resolve before I make the transition to printing on FB paper.

1. How is using a two-bath fix any different from using a one-bath fix that is replaced more often?

My hunch is that using a two-bath fix breaks up the paper's exposure to the fixer into two parts, which reduces the extent/depth to which the fixer is absorbed by the fiber-based paper, which is a good thing. But I'm really not sure.

2. At what stage in paper processing do you introduce the print into the second fixer bath? Is it developer->stop->fix #1->h2o rinse->fix #2->washing aid->h2o wash?

3. Ilford's PDF on "Processing FB Papers" seems to suggest that the two-bath fix is an *alternative* to using a washing aid like Kodak HCA. Is this so? Would it be 'safer' (read: imparting significantly more stability to the prints) to use both washing aid as well as the two-bath fixer?

This forum has really proved to be a godsend, and any and all replies will be appreciated. Thanks in advance.

 

[Nick Zentena]

The main advantage of two bath fixing is it greatly extends the life of fixer. Fixer VERY quickly stops being able to archivally fix. But at this point the fixer can still do the vast majority of the fixing. You could use fresh fixer for every print and I guess that would be no worse then using two baths.

it's just 1/2 the time in bath 1 then 1/2 in the bath two. Nothing in between.

 

[photobackpacker]

It also allows for a break in the process. I usually do a single 2-minute fixing bath (f-6 formula) and then into the holding tray with fresh water. At the end of the printing session, I mix a bath of pre-toning fixer (no acid, no alum), process all of the prints that will be toned in this solution and then into the toner. There are many prints that go to the trash can before this step. For each of those, I have saved the fixer and more importantly, the time.

It is possible to wash and dry the single fixed prints and then return to a presoak, pre-tone fixer and toning process as well. This, too, can be a real time saver.

 

[Gerald Koch]

The reason for using two fixing baths is that the majority of silver will be removed in the first bath. The small amount remaining will then be removed in the second bath. This assures that the amount of residual silver in the print will be lower with a two bath system than with a single bath. Residual silver in prints can cause staining. When the first bath nears saturation it is replaced by the second bath and a fresh second bath used.

 

[smieglitz]

The reaction in the first fixing bath causes relatively insoluble silver-thiosulfate compounds to form. These byproducts, harmful to the print if not removed, are dissolved in the second fresher, (and therefore) stronger fixing bath.

According to what I've read (Ilford's recommendations, etc.), you are better off using two successive baths of film-strength fixer for about 30 seconds each and then a quick rinse in water followed by the clearing agent (5 minutes) and final wash.

Having a water tray/holding bath between fixers is not a good idea because it essentially becomes a weak fixing bath that the prints sit in and absorb into paper fibers making it very difficult to remove. Do the quick strong 2-bath fixing method instead and get those prints into the clearing agent quickly for best and most archival results.

joe

 

[Tom Hoskinson]

I'm with Gerald Koch and joe smeiglitz on this one! I strongly recommend and practice two bath fixing for the same reasons they put forth. Another voice on this subject (one strongly recommending 2 bath fixing) is provided by Grant Haist. See page 645 in Modern Photographic Processing by Grant Haist.

 

[lee]

I'm with Gerald Koch and joe smeiglitz on this one! I strongly recommend and practice two bath fixing for the same reasons they put forth. Another voice on this subject (one strongly recommending 2 bath fixing) is provided by Grant Haist. See page 645 in Modern Photographic Processing by Grant Haist.

Add my voice with Gerald and Tom and Joe on this. Two bathes are better than one.

lee\c

 

[dancqu]

... (one strongly recommending 2 bath fixing) is ... Grant Haist.
... in Modern Photographic Processing by Grant Haist.

Modern? IIRC the year was 1855 when thiosulfate
was found to dissolve silver halides. BIG step forward
for silver whatever photography. The following year,
two bath fixing was found to be better. Wouldn't
swear to the exact date though.

It dawned on me a while back that the very dilute
one-shot fix I've been using was producing archival
results with a single fix.

To mark the 150 anniversary of the discovery of
the thiosulfate fix, I offer the Single Bath Very Dilute
One-Shot Archival Fix. Fast and great milage. Dan

 

[Daniel Lawton]

FWIW I use the Formulary's TF-4 which is a pretty sturdy fix with long life and capacity so I don't bother with a 2 bath fix. If I had any problems with inadequate fixing it would show up rather quickly when I selenium tone my prints. If I'm not mistaken, an improperly fixed print would display staining and blothches when toned. Since I haven't experienced this I see no reason to bother with a 2 bath method. Also, selenium toner contains fixer so wouldn't this act like a second fixing bath in a way, thus ensuring complete fixing?

Dan

 

[fhovie]

FWIW I use the Formulary's TF-4 which is a pretty sturdy fix with long life and capacity so I don't bother with a 2 bath fix. If I had any problems with inadequate fixing it would show up rather quickly when I selenium tone my prints. If I'm not mistaken, an improperly fixed print would display staining and blothches when toned. Since I haven't experienced this I see no reason to bother with a 2 bath method. Also, selenium toner contains fixer so wouldn't this act like a second fixing bath in a way, thus ensuring complete fixing?

Dan

I have suffered from bad fixing - The prints on the wall start to change color in a year or less. This is very embarassing. I have not had trouble since I have adopted the practice of putting a slip of film in my paper fixer at the end of a session. If it takes more than 60 seconds to clear - I make freash and re-fix the batch. Fresh TF3 fixes the film in 30 seconds.

 

[mmcclellan]

I think the main issue with all of this is that in a two-bath system, the second one should be plain hypo (no hardener) if you plan to selenium tone. If you're not toning, a two bath system cannot hurt and MIGHT be more archival -- given that it takes no longer to do, it's well worth the effort.

For toning, however, the second bath should be hypo and then go right into the toner and hypo clear.

 

[Gerald Koch]

The two bath system is also more economical since the first bath can be used longer than a single bath fix. There is also less impact on the environment.