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Discussion in 'B&W: Film, Paper, Chemistry' started by Greg Davis, Nov 22, 2010.
Here's the relevant paras from LFA Mason "Photographic Processing Chemistry" (2nd Ed):
Thanks PE and pdeeh for all three replies.
You may well be right, pdeeh about 5,10,20,20. A trawl through the mass of Ilford stuff may well reveal that its literature does cover this. It does after all mention a 5-10 min wash in continuous running water as well.
It may even mention the invert then sit for a time and then dump method. I haven't managed to find it but there is a lot of stuff there.
There is no question that in the straight 5.10, 20 fill, invert and dump method without a "sit "period as mentioned in the article I referred to that it allows for less time for diffusion to take place than is true of even 5 mins of running water.
I suppose that only time will tell if the "invert and the immediately dump method" has repercussions for film longevity. If the period is long enough then for most users a deterioration in the film may not matter.
My parents and grandparents probably had a lot of films processed over their lifetimes but while a few prints in albums remain, the negatives in nearly all cases sadly vanished. It was as if only the prints( the fruit) mattered instead of the seedcorn( the negatives) which allow another harvest
I suspect that this experience is not confined to my family
All the discussion about the "Ilford Method" here makes me smile. Even in their "Processing Your First Black and White Film" guide they list different wash methods in different parts of the document.
At the beginning:
In running water for 5 _10 minutes or. . .
In ten changes of 20°C/68ºF water each lasting one minute.
And then later in the same document:
Now the film is fixed you can remove the tank lid.
If you have running water at about 20°C/68ºF,
use a piece of rubber tubing to feed this down the
centre of the spiral to the bottom of the tank. Wash
the film in running water for about 5 to 10 minutes.
Alternatively, fill the spiral tank with water at the
same temperature, +/– 5ºC (9ºF), as the
processing solutions and invert it five times. Drain
the water away and refill. Invert the tank ten times.
Once more drain the water away and refill.
Finally, invert the tank twenty times and drain the
Here is the link: http://www.ilfordphoto.com/Webfiles/200629163442455.pdf
Well Matt, I think we all know what we're referring to. there's no real ambiguity in this case, and finding counterexamples or inconsistencies can just muddy the water (haha)
As Gerald said in a recent thread on testing fixer for exhaustion, the point is to make sure your end result is what's wanted - in this case, thiosulfate-free (within reasonable limits) film emulsion.
accordingly, if someone applies a method consistently, and tests for the result, then it doesn't matter a jot whether they wash their film in their own pee whilst whistling Dixie, or in an "archival washer", so long as their film tests as thiosulfate-free afterwards. Once that's established, carry on ...
and as PE has pointed out on many occasions, if anything changes (like you move to an area with different water) you need to test again to ensure your method is producing the result you want.
At last, six pages to reach this point, Bravo!
Well, its by no means the last word on the subject & nor should it be taken as one, especially not from someone as unqualified as me.
Like many "technical" issues, this one gets raised and discussed almost, it can sometimes seem, endlessly. Search "washing" on APUG and the results run to tens of pages!
I don't see any harm in that, despite all those who grumble that people should just "read the archives", because new ways of explaining and understanding these issues emerge during the discussion, and people who had never considered or are completely new to the subject can find out something they didn't know before.
as ever, the trick is to pick the wheat from the chaff, and dogmatic assertions with no scientific basis can easily become internet lore - and for some, darkroom law.
Well, then we should be able to take into account more often and with humbleness one opinion without experience and (like you've said above) as a new way of explaining and understanding things. In fact - in this case and to my way of thinking - that "accordingly" quoted I see it very much as the most sensible or reasonable one in the whole thread.
As for the harm you do not see ... perhaps with a poem:
keep in mind or pay especial attention
both the excess and the lack of information.
Centainly we can not forget to mention
the electronic behaviour or human relation
I agree it won't be the last word
I am fully in agreement of personal testing but I wonder what chemicals in water deemed of drinking quality would prevent thiosulphate diffusing out of the gelatin across a concentration gradient into the wash water?
the hardness of the water can affect the degree of gelatine swell and thus the rate of diffusion
An add-on to the Ilford method is to remove reels and shake excess water out between cycles.
I would have thought that by the time we arrive at washing the gelatin has no more swelling to do, is it an effect like a hardening fixer perhaps, if it does that at that stage.
Total hardness as calcium carbonate. Kodak suggests this be in the range of 40 to 150 ppm, with 40 being the preferred end. Too high a level limits the swelling of the gelatin and leads to delayed entry of the developer.
I have been too lazy to check why I think it's to do with hardness and gelatine swell, but my feeling was that it was something PE wrote ina post in one of the other dozens of threads on the subject of washing. But as we know, memory is often terribly unreliable, and regardless of how convinced I am that that I am remembering correctly, the chances are that I am not (remembering correctly)
Indeed I am sure this has been covered at some point but I had just read the Mason paper kindly quoted above which despite PE's caution because it contain equations seemed one the most straightforward expositions on the subject.
I will withdraw and carry on washing.
Calcium, Magnesium, Iron, Sulfates, Sulfides and absolute pH value are just a few things that affect wash rate.
Haist shows a swell profile of a photographic material being processed, and I have run many myself.
The Mason paper disregards all these variables then, for the sake of simplicity no doubt, which puts us back to individual testing rather than a general method which of course is a proven starting point. The OP of this thread produced an excellent model to follow but, unless I recollect incorrectly, did not provide an analysis of the water used which, given that list of variables, and the inability for most individuals to test or indeed guarantee day to day continuity inevitably means giving a safety margin (where have I heard that term in photographic usage before ) .
Mason apparently did consider all of these variables. His outward diffusion is a function of all of the above items and more, such as absolute swell, halide ion and other ionic and non-ionic salts such as Na+ vs NH4+ vs SCN- and etc. If he did not, then we at least did.
In the end, Haist was working on thermally processed materials which were not washed and which had great stability.
Apologies for my simplification of Mason, his constant, k, allows for that, the problem being my k is not your k. As a theoretical ( and practical if you have the facilities to determine k) value it facilitates his explanation but leaves us self testing.
This for me is the take home: whatever the method or the materials (water quality) self testing can be the only way to be sure.
Has this been posted for reference?
Yes, that was posted many pages back
Many of us have posted the above here on APUG.
In addition, that "k" of Mason's is why I suggest testing for your conditions and re-testing if they change. Nothing can replace a good test and nothing can tell you more rapidly if you have erred.
I am sure I have.
Thank you Greg and PE for the posts on the .pdf.
Yesterday I noticed that my rapid fixer concentrate had sulfurised, so I had to scratch mix some non rapid, non hardening, sodium thiosulfate based fixer (F24). Having never used a non rapid fixer, I had no idea how easy it would wash, but luckily I have made some HT2 solution. I processed a roll of 400TX, which was fixed for 10'. After fixing I did a quick rinse, which was followed by a 2' wash in a 2% sodium sulfite solution. I didn't want to use running water for the wash, primarily because tap water can get quite bellow 20°C, so I opted for several water changes. I filled the tank with ~500ml water, agitated for about 1' and let it rest for 4 more minutes. After the 5th water change I remembered that I had some HT1 solution that I could use. The result suggested that the film is already washed. There was no colour change whatsoever, a clean permanganate purple, but to be on the safe side I decided to do 2 more changes for a total of 7.
Today I checked the film with the HT2 solution and there was absolutely no staining after 2', a sign of very clean film. So, water changes are a viable option for washing film, even when using sodium thiosulfate based fixers. But in any case, if you want to be sure about your technique, invest in a few grams of silver nitrate for the HT2 test solution.
I just found the Ilford document where I got my idea that it was a 5,10,20,20 wash sequence - its in this PDF which describes reversal processing
That is well found.
It is however somewhat contradictory:
First wash is 5,10,20,20 or running for 5 minute
Second wash same regime or 1 min running
Third wash or 1 min running
Fourth 1 min again
Fifth same regime or 10 minute running.
From this are we to suppose the Ilford regime is equivalent to a one minute running or a ten minute running ?
If, as it seems, 10 minutes equivalent then a reduced regime for the 1 minute wash would be sufficient ie only one 20 change would it not?
The "at a glance" table at the end seems to prefer the running option for first and last washes which is not reflecting the text where running "may be substituted".
Mason says (p201) "Excepts for rapid processing systems, it is usual and preferable to pass the film, etc., through a short washing stage between different processing solutions. Such washes range from a few seconds rinse to several minutes washing, but these washes are never sufficient to effect complete removal of the constituents of the preceding bath. Their main objective is to reduce the contamination of the subsequent bath by the constituents of the former bath."
I think it's important to point out that for all but the final wash (#5), these rinses serve a different purpose than removing silver complexes and thiosulphate from the film for archival stability.
#1 is there to avoids interaction between FD and bleach which can result in chromic sludge (or MnO2 if using permanganate bleach) being deposited onto the film, tank, and reels. You need strong acid to solubilize these if they form.
#2 lengthens the active life of the clearing bath.
#3 removes the sulphite so as to minimize its solubilizing effect on AgX
#4 helps to wash out developer, lengthening life of the fixer.
#5 washes out thiosulphates for long term stability.
As you can see, these serve different purposes. #5 is a the same type of wash discussed in this thread, and failure to complete it will lead to reduced stability. #1 is also important for the results of the processed film, so a longer wash is recommended. I am the first to admit I do not understand why Ilford recommends the 5,10,20,20 as equivalent to the running water washes of different lengths of times. I will point out that if you look at the bottom of the document, you will see a table outline the entire reversal process and you will see that for wash #1 it says "Preferably running water" and #5 it simply says "running water".