How do you process Fiber base or Barite double weight enlarging paper ?

[Luis-F-S]

Actually that toning process sounds no different from what Fred Picker taught over 30 years ago: tone in selenium bath, move to hypo clearing tray, then wash as you would any newly made print, since the selenium toner contains hypo. Separating the hypo clear step from the toning step has the added virtue that you can reuse the toner pretty much indefinitely, with straining through a filter and the occasional addition of fresh selenium toner when toning times get too long. The hypo clear gets discarded after use.

+1!! Thankfully I still have a bunch of old paper frozen from 30 years ago.

[Leigh]

The first bath does most of the work, leaving the second bath fresh for much longer.
The capacity of the fixer can be greatly extended this way (about 35-40 8x10s per liter of first fix).

This makes no sense.

Fixing is a chemical reaction that proceeds at a fixed rate.

The first bath has no way of knowing that there's a second bath.

Are you suggesting that the time in the first bath is reduced by 50% or 75% or whatever?

- Leigh

[Doremus Scudder]

This makes no sense.

Fixing is a chemical reaction that proceeds at a fixed rate.

The first bath has no way of knowing that there's a second bath.

Are you suggesting that the time in the first bath is reduced by 50% or 75% or whatever?

- Leigh

Leigh,

I'm simply describing two-bath fixing, a practice that is common and time tested. Total standard recommended fixing time is divided between two baths. The first bath starts out fresh, so fixes very quickly at the beginning. As this first bath collects more and more dissolved silver, the fixing rate slows. Still, the bulk of the work gets done there and the bulk of the fixed-out silver gets dissolved into that first bath. The second bath, at first, has little if anything at all to do, but as the first bath ages, does get a small workout, but nothing like the first bath. The idea is to keep the dissolved silver in the second bath low enough that prints are processed to optimum permanence standards.

Keep in mind that recommended print fixing times are based on the time it for the last print through to fix to a certain standard. Fixation for earlier prints is less in proportion to the degree of fixer exhaustion. Same applies for film; why do a clip test if fixing rate doesn't change with fixer exhaustion.

Here's Ilford's explanation from their tech sheet on Rapid Fixer:

"Two bath fixing
An extremely efficient method of fixing film or paper is to use the two bath fixing technique. Make up two separate fixing baths of the same solution volume. Fix the film or paper in the first bath for half the recommended fixing time and then transfer them to the second bath for the remainder of the time. Continue to work this way until the capacity of the first bath is reached, then discarded it and replace it with the second fixer bath. Prepare and use a completely fresh second bath. Repeat this process as required with the
result that the film or paper is always thoroughly fixed by the relatively fresh fixer in the second bath:"

Best,

Doremus

[Pere Casals]

This makes no sense.

Fixing is a chemical reaction that proceeds at a fixed rate.

The first bath has no way of knowing that there's a second bath.

Are you suggesting that the time in the first bath is reduced by 50% or 75% or whatever?

- Leigh

If I'm not wrong, first fixer bath is well reused and have diluted silver. When you remove the print from that bath it happens that emulsion is wet with a liquid (fixer) that contains silver and bromide, I guess that when you wash paper emulsion you don't wash fixer only, you wash fixer + silver + bromide. So perhaps some silver bromide could precipitate again in the emulsion as fixer concentration lowers with washing.

If you use a second fixer bath then that silver contaminated fixer that is inside the emulsion is diluted in all the clean/fresh 2nd fixer, so the silver that remains in the emulsion when washing with water is divided by a large factor, perhaps 1/1000, ...if you use that second bath.

So with second bath you get 2 things: 1) perfect job, 2) you can extend 1st fixer reuse without damaging the print.

When 2nd fixer has some significative silver in it... then you use it as 1st fixer and make the 2nd fix with new fixer. The fixer lasts more, and you do a perfect job.

This is IMHO, what I understand...

[Oren Grad]

Ammonium thiosulfate rapid fixers allow for faster fixing. A desired side effect of this is that, if you use relatively strong fixer, you can get the fixing times down to about 1 minute. This short fixing time keeps the fixing chemicals from penetrating deep into the base of the paper, which makes washing easier and shorter.

You can check out Ilford's recommendations on this procedure at their website. In short, it entails using their Rapid Fixer or Hypam at the "film" dilution, i.e., 1+4, and a one-minute total fixing time. With a wash-aid (hypo-clear) step, the wash time is reduced significantly.

More traditional fixing and washing regimes use a weaker fixer for longer (I use Ilford Rapid Fix or Hypam at 1+9 dilution for 3 minutes total). This requires a longer wash time, but, especially for larger prints, is easier to manage than the shorter fixing times. Whether you choose to use the shorter regime or the longer one is a personal choice.

One thing I want to add to Doremus's otherwise excellent discussion is that you can't assume that all papers work well with 1-minute fixing. It's been a long time since I used much in the way of non-Ilford papers, but my recollection from years past is that some papers from other brands did not clear adequately within that time. If there's any doubt:

Careful workers test their process with tests for residual silver (fixing test) and residual hypo (washing test)....

[interneg]

One thing I want to add to Doremus's otherwise excellent discussion is that you can't assume that all papers work well with 1-minute fixing. It's been a long time since I used much in the way of non-Ilford papers, but my recollection from years past is that some papers from other brands did not clear adequately within that time.

Fomatone is about 1m 30s, Fomabrom & pre-Harman Kentmere are more like 3m. Fomalux is 1m, I recall.

I seem to remember this has to do with the quantity of iodide in the emulsion which both slows fixing & exhausts fixer faster - I'd need to check on this though.

[alberto_zh]

Gudmundur the way Oliver taught us. I still develop, fix, wash & tone like I did 20 years ago. I have Oliver's notes still if you misplaced yours. L

Care to send them over to me, if possible? Much appreciated


Sent from my iPhone using Tapatalk

[Doremus Scudder]

Oren,

Many, like me, find the one-minute times not only risky with non-Ilford papers, but also impractical and too hectic. I can hardly drain a 16x20 print in 30 seconds; draining it twice from two fixing baths is one minute. I'm at the limit of time for achieving a shorter wash and haven't even included the fixing time!

My preference is for longer fixing times with weaker fixer (as Kodak recommends), followed by a hypo-clearing bath and then a longer wash. I use Hypam or Rapid Fixer 1+9 for printing now, although TF-5 looks like a really good product and will likely find a place in my darkroom in the future. But, then I'll have to test my work-flow again, so not till I have time.

Best,

Doremus

[Pere Casals]

Ilford datasheet tells all:


Two bath fixing

An extremely efficient method of fixing film or
paper is to use the two bath fixing technique.
Make up two separate fixing baths of the same
solution volume. Fix the film or paper in the first
bath for half the recommended fixing time and
then transfer them to the second bath for the
remainder of the time. Continue to work this way
until the capacity of the first bath is reached, then
discarded it and replace it with the second fixer
bath. Prepare and use a completely fresh second
bath. Repeat this process as required with the
result that the film or paper is always thoroughly
fixed by the relatively fresh fixer in the second
bath.

http://www.ilfordphoto.com/Webfiles/...7111531653.pdf

Single reason I find to not using the 2 bath is having an small darkroom and big trays. With 2 bath one has no doubt with fixing even when 1st fixer is near of its end of cycle, because 2nd fixer is always near fresh, and 2nd fixer is reused as 1st fixer when the former 1st fixer is exhausted. So less waste as one can exhaust fixer without problems, and having always a perfect job.

Also they say:

> 2min for FB at 20ºC.

> Reading the rest it can be concluded that if fixer is under 20ºC give more time, if is +25º you can fix less time if one wants to check fixing speed.

> Also they explain in "CHECKING AND MAINTAINING FIXER ACTIVITY" section

[N Dhananjay]

Just to clarify about the extended life in a 2 bath system. The initial results of fixing are early byproducts that are highly adsorbed into the fibers of the paper and as a result they do not wash out easily, or at all. As fixing proceeds to completion, these early byproducts react with the fixer to form soluble byproducts that are are a lot easier to wash out. As you continue using the fixer, there is obviously an accumulation of these complex byproducts in the fixing solution itself that reduces the ability of the fixer to completely fix and runs the risk of adsorption of these byproducts in the paper fibers. I believe the primary benefit to a two bath system is that the first bath does the heavy lifting and the second bath sees very little of the complex byproducts. As a result, there is some comfort in knowing that fixing has proceeded to completion. Since all the byproducts are late stage, easy to wash ones, washing is relatively easy as well. The 1 bath rapid system works using a rapid fixer, and when it works, it reduces the tendency for the byproducts adsorbing into the paper fibers, and is thus easier to wash out. However, this calls for a balance where the fixer is working fast enough to finish all the complex stages of the fixing process within the small window of time to prevent adsorption.

I have not seen any data to the fact that a 2 bath system offers more fixing capacity (that does not mean there is no such evidence, just that I have not seen it). However, the 2 bath system is a more relaxed processing regimen, as alluded to by Doremus above. Slop in the system due to draining times, especially for larger papers etc. make it arguably easier to use. I do not know if it actually results in larger capacity. My own guess is no - because if you overuse the first bath, the second bath has to start doing the heavy lifting and that would reduce its capacity when it starts being used as the first bath. I think the main reason for a 2 bath preference is that the balance point is much wider - it is not balanced on a knife point. There is more room for user error without running the risks of inadequate fixation or difficult washing.

Cheers, DJ