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  1. #11

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    the long run, I am keen to experiment with removing the second fix bath, since I think the thiosulfate in KRST, and then a fresh washing aid, perhaps slightly prolonged from my current 3 min to 5 or so, may do a good enough job of getting rid of the fixing byproducts. But first, I just want to try with a neutral one.
    To simplify, reduce fumes and process to an archival standard I initiated the following process. Non metol print developer, water stop, TF-4 fix. Fix capacity is (10) 8x10s per L. There are no fumes with this all alkaline process. If I print on 11x14, I introduce a citric stop, water rinse and two tray fix. The citric stop aids in a quick stop with such large paper. I always lightly tone and use a (10) minute wash aid before a 20-30m manual tray wash.

    The down side is lower fix capacity with a one tray line. The positive is a citric stop will be ok when used with neutral fix like Ilford's if processing only (10) 8x10s per L.
    RJ

  2. #12
    Rafal Lukawiecki's Avatar
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    Richard, if you do a two stage fix you should be getting a much higher capacity out of the first fixer.

    I believe, but I have not verified in tests, yet, this may also apply when using a single stage fix with a fresh and unoxidized wash aid after fixing, which effectively allows a higher fixer capacity.
    Rafal Lukawiecki
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  3. #13
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    Would a flowing water rinse between the stop and fix solve your problem?
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  4. #14

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    The one stage fix was suggested as a way to simplify with the down side of less capacity. You wrote in a later post the desire to eliminate the second fix.
    I prefer using non metol paper developers. PE suggested an acid stop is required to eliminate developing agents if using metol.

    I recently started to use a weak citric stop for prints larger than 8x10. No irritating fumes were experienced. To reduce solution carry over I use a water rinse after the citric stop and finish with a two fix process. The larger prints (8x12) on 11x14 are to be mounted. In my limited space its easier to use a single tray processing routine when projecting on 11x14. The downside is cleaning the tray between each processed print. Otherwise I use 8x10 trays, water stop, and one fix tray to make it simple.
    Last edited by Richard Jepsen; 03-12-2013 at 11:56 AM. Click to view previous post history.
    RJ

  5. #15

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    Just a few observations:

    I transfer prints directly from a rapid fix mixed "paper strength" or 1+9 (Ilford Hypam or Rapid Fix, or Kodak Rapid Fix without hardener) to the selenium toner. No problems with staining, etc. The fixer is neutral enough to not need an intermediate rinse. My point here is that mixing your own fixer might be overkill and not get you any better results at the expense of wasted time.

    I use two-bath fixing. Capacity is ca. 40 8x10 per liter. Richard might find it worth it to cut his capacity by 75% for convenience sake, but I do not. The total fixing time remains the same anyway. I really cannot understand the objection to two-bath fixing unless it is the space issue. Maybe there are better ways to deal with not having enough tray space than risking the permanence of your prints or wasting 75% of your fixer. Tray stackers are a pretty good solution and I've used these often for larger prints. Normally however, I solve the space problem by separating the toning from the printing (see below).

    A wash aid is not going to increase the capacity of any fixer. It will speed up washing but it won't chemically change any insoluble silver thiosulfate compounds. You need adequate fixing in fresh fixer to achieve complete fixing. If you want to use single bath fixing and still have optimum permanence, Richard's ten 8x10s per liter is the correct capacity (according to Ilford and others). Two-bath fixing gets around the capacity limitation by having a relatively fresh and uncontaminated second bath that finishes fixing the insoluble compounds left by the first bath after its capacity of ten prints has been reached.

    The amount of thiosulfate in KRST does not make it a fixer, nor does the toning bath function as a fixer. Plus, if you try to use your toner as a second fixing bath, you'll have to toss it when the fixing capacity is reached, well before the capacity of the toner is reached. Uneconomical and environmentally irresponsible. (Do a search for some of my posts on replenishing and reusing selenium toner so you won't ever have to toss it.)

    Commercial fixers like the ones I have mentioned are designed to be used with an acid stop bath. Don't mix the stop bath too strong and drain your prints well before transferring them to the fix and you should be fine. Whether you use one or two-bath fixing, the fix won't die from "acid contamination" before you reach its capacity when transferring directly to the fix from the stop. You don't need a water bath between stop and fix at all; it is completely superfluous. Why would you want a process that added yet another step without getting any better results? (plus, you could use the extra space for a second fixer tray...)

    Indicator stop baths mixed a bit weaker than recommended (2/3 recommended strength or so) do not have much odor and work just fine; they just have a smaller capacity. Toss the stop when it just begins to turn color.

    Neither fix at "print strength" nor a weak stop have a whole lot of "fumes." I notice almost no odor at all except when I mix a fresh stop bath. If you are dealing with a lot of odor, you might need to deal with ventilation problems before trying to find more odorless chemicals.

    To optimize your processing space, you might try dividing your work flow and separate the toning session from the printing. I develop, stop, give fix one, then wash and dry prints. The toning session is a water soak, fix two, toner, hypo-clear and wash. Doing all that stuff at once is just to much and takes too much room. Plus, I can live with the prints for a while and discard the prints that I don't think will make the grade before toning. This keeps me from spending a lot of toning time on reject prints.

    Just some ideas...

    Doremus


    www.DoremusScudder.com
    Last edited by Doremus Scudder; 03-13-2013 at 12:20 PM. Click to view previous post history.

  6. #16
    Rafal Lukawiecki's Avatar
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    Matt, Richard, Doremus, thank you for putting your time into sharing your thoughts with me.

    Doremus, you make good points about your process, which clearly works well for you. I am inquiring specifically about making improvements to mine, which is, at the moment, very similar to your current process, yet which I wish to improve by taking advantage of the more recently available knowledge, and the collective wisdom of the community. I hope you will not be offended, however, if I politely question two points, which you have made, and which I think were the core of my inquiry, ie. re-evaluation of the use of sodium sulfite, and the presence of thiosulfate in KRST. I look forward to your, or other chemists' feedback, as I am not a chemist myself, although I do have an appreciation of the basic photochemical concepts.

    Quote Originally Posted by Doremus Scudder View Post
    A wash aid is not going to increase the capacity of any fixer. It will speed up washing but it won't chemically change any insoluble silver thiosulfate compounds. You need adequate fixing in fresh fixer to achieve complete fixing. If you want to use single bath fixing and still have optimum permanence, Richard's ten 8x10s per liter is the correct capacity (according to Ilford and others).
    Ilford states: "Use a single fixing bath plus a washing aid. The number of prints through the single fixing bath can be increased to approximately 40 8x10" prints per litre working solution." in this document, page 3, right-hand column, point 3. This is in contrast to what they say is the capacity without a wash aid: "Fix only a few prints before replacing the fixing bath (approximately 10 8x10 inches prints)."

    Similarly, you will find an extensive comparison of fixing and the fixer capacities, with and without the use of a washing aid, in this publication of Digital Truth, which is very similar to Ryuji Suzuki's findings, and on the Pure Silver mailing list. That document states: "Note that the processing capacity of fixer is considerably lower if fiber prints are processed without using a washing aid" and the capacity numbers show between twice and four times larger capacities of the fixer when a wash aid is part of the process. I think I saw a Kodak reference, similar to those two, but I cannot find it anymore.

    So, why is the use of a wash aid, such as a 2% solution of sodium sulfite, able to increase the capacity of the fixer to the level almost identical to that achieved when using two-bath fixing? Based on what I have read it has to do with the removal of the silver thiosulfate compounds, as there is very little silver halide left in the emulsion of the paper when fixing even for a shorter time with a non-fresh fixer, but one that isn't exhausted, yet. I was re-reading Mees today (chapter 13, Fixation and Washing), while preparing to write this post, and I am always amazed by the complexity of the seemingly simple fixation process. However, I can surmise that two things are relevant to my question: as long as we are using fixer that is no longer fresh, but not exceeding silver levels of 2g/litre (so about the capacity of 40 8x10 sheets in ammonium thiosulfate 12% solution, such as a typical rapid fixer), there will be a build up of argentothiosulfates, or if you prefer silver thiosulfate compounds, including those that Mees refers to as salts of the argentothiosulfuric acids (page 512 edition 1 of The Theory of the Photographic Process), or what Gudzinowicz calls monoargentomonothiosulate, monoargentodithiosulfate, and monoargentotrithiosulfate, while describing their increasing levels of solubility. From what I read, those compounds are likely to migrate from the emulsion to the solution only when a fresh fixer is used, less than 0.5g silver/l (up to about 10 sheet 8x10 per l, which you mention), or when the print is moved to the second, such fresh fix bath. A fixer than is more exhausted will cause some of those compounds, including the more soluble ones, to adsorb to the silver grains, and also to the other layers in fibre paper, especially if fixation is anything but very brief.

    However, what complicates this picture is the fact that it is even the more soluble argentothiosulfates will also form anew on the surface of the emulsion, if the fixer is sufficiently unfresh, as mentioned in this patent by Armstrong, in which he describes the efficacy of wash water being increased by the presence of certain levels of impurities, due to ionic exchange. This is also discussed in the 9th ed of "The Manual of Photography" by Jacobson, page 294: "In the presence of a high concentration of soluble silver, or low concentration of free thiosulphate, when the fixing solution is nearing exhaustion, the complex sodium argentothiosulphates may become adsorbed,or "mordanted", to the image. These are difficult to remove by washing." Notice the comment "difficult" rather than "impossible".

    Now we come to sodium sulfite. Not much I could find, but there are references to it acting this way: "sulfite can desorb not only unreacted thiosulfate but also sparingly soluble and adsorbed argentomonothiosulfate complex" (arguably not the most reliable source, Photography Wiki). I can see references in David Locker's paper, but I do not have access to it, and Wiley quotes a low price of just $12,346 for a one-time access. However, since Ilford, and others, are quoting this action of sodium sulfite, there must be a reason, and I would love to know what it is, or if something else is at play, that increases the effective capacity of the fixer, while maintaining archival/optimum permanence.

    Quote Originally Posted by Doremus Scudder View Post
    The amount of thiosulfate in KRST does not make it a fixer, nor does the toning bath function as a fixer. Plus, if you try to use your toner as a second fixing bath, you'll have to toss it when the fixing capacity is reached, well before the capacity of the toner is reached. Uneconomical and environmentally irresponsible. (Do a search for some of my posts on replenishing and reusing selenium toner so you won't ever have to toss it.)
    Doremus, I hope I did not make it sounds like I was ever suggesting that KRST is a fixer. If I did, please accept my deep apologies for not making myself clear: indeed, KRST is a well-known selenium toner, and not a fixer. If one were to use it on a not fully-fixed sheet, staining would result, as selenium would react with silver halides.

    I am merely curious, however, if the presence of 3-5% of fresh ammonium thiosulfate in a working strength KRST (it holds 25-30% in stock according to its MSDS), which is almost the same as a paper-strength rapid fixer, would have a positive effect on the process of desorbing of the complex argentothiosulfates. I hope you will agree this is a valid question to ask, and I would be surprised if no one has thought of it before. I realise, however, that the action of the fixer that is responsible for the conversion of the silver halides to argentothiosulfates is easily retarded by the presence of other ions, such as chloride, bromide, and especially iodide, but I have no idea if selenium would have this impact on the desorbing function. Perhaps you could help me in this.

    I very much appreciate your concerns for the environment, and I have, for many years, read your posts here and on the other forum. Perhaps you may have noticed my posts about recycling and environmentally sound removal of photographic chemistry, as it is a subject of great importance to me, and to the place where I live. I trust you see that there is an environmental aspect to my quest in process optimisation: removing a fixing stage and replacing it with something many of us do anyway (wash aid) will cut down on disposed fixer on every 2-stage final rotation, regardless of what is done with the toner.

    I look forward to your comments, and I apologise to all chemists for any shortcomings in my post.
    Last edited by Rafal Lukawiecki; 03-14-2013 at 01:25 PM. Click to view previous post history.

  7. #17

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    [QUOTEIlford states: "Use a single fixing bath plus a washing aid. The number of prints through the single fixing bath can be increased to approximately 40 8x10" prints per litre working solution." in this document, page 3, right-hand column, point 3. This is in contrast to what they say is the capacity without a wash aid: "Fix only a few prints before replacing the fixing bath (approximately 10 8x10 inches prints)."][/QUOTE]

    The ilford 40 print reference is for processing to a commercial archival standard (7-10) years. If you use a wash aid you may extend the Commercial capacity of a one tray fix. The fix has a capacity to process maybe 80 to 100 prints but as more prints run through the fix the more silver thiosulfate compounds build up reducing print life.

    If you limit fix capacity to (10) 8x10s per L, you don't need a wash aid to obtain optimum permanence without toning. If you tone, you must use a wash aid for optimum permanence.

    I'm a simple guy. If your capacity is high, you can explore ways to recover silver. There seems to be a desire for one fix tray and higher capacity. One could just use RC paper which allows higher capacity and uses less water.
    RJ

  8. #18

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    Quote Originally Posted by Richard Jepsen View Post
    Ilford states, "Use a single fixing bath plus a washing aid. The number of prints through the single fixing bath can be increased to approximately 40 8x10" prints per litre working solution." in this document, page 3, right-hand column, point 3. This is in contrast to what they say is the capacity without a wash aid: "Fix only a few prints before replacing the fixing bath (approximately 10 8x10 inches prints)."]
    The ilford 40 print reference is for processing to a commercial archival standard around (7-10) years. If you use a wash aid you may extend the Commercial capacity of a one tray fix. The fix has a capacity to process maybe 60 to 80 prints but as more prints run through the fix the more silver thiosulfate compounds build up reducing print life.

    If you limit fix capacity to (10) 8x10s per L, you don't need a wash aid to obtain optimum permanence without toning. If you tone, you must use a wash aid for optimum permanence.

    I'm a simple guy with a dry unvented DR. If your print capacity is high explore ways to recover silver. There seems to be a desire for one fix tray and higher capacity. Recommend RC paper which allows higher fix capacity and uses less water.
    Last edited by Richard Jepsen; 03-14-2013 at 07:22 PM. Click to view previous post history.
    RJ

  9. #19
    Rafal Lukawiecki's Avatar
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    Richard, did you have a look at that Ilford page? My reading is that they describe 3 equivalent approaches in the section on the right of page 3, specifically equating with each other: 1. Fixing up to 10 sheets of 8x10 in 1l. 2. Fixing in a two bath fixer. 3. Fixing up to 40 sheets in one bath when using washing aid.

    Since 10 sheets per litre is what you describe as archival, and since they suggest that is equivalent to 40 sheets with wash aid, it would seem to imply that 40 plus wash aid has to be as archival as 10 without it. Digital Truth seems to suggest that too.

    Perhaps I am not reading that correctly...
    Rafal Lukawiecki
    See rafal.net | Read rafal.net/articles

  10. #20

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    Quote Originally Posted by Rafal Lukawiecki View Post
    ... Doremus, you make good points about your process, ... I hope you will not be offended, however, if I politely question two points, ...

    Ilford states: "Use a single fixing bath plus a washing aid. The number of prints through the single fixing bath can be increased to approximately 40 8x10" prints per litre working solution." in this document, page 3, right-hand column, point 3. This is in contrast to what they say is the capacity without a wash aid: "Fix only a few prints before replacing the fixing bath (approximately 10 8x10 inches prints). Similarly, this publication of Digital Truth, which is very similar to Ryuji Suzuki's findings, and on the Pure Silver mailing list. That document states: "Note that the processing capacity of fixer is considerably lower if fiber prints are processed without using a washing aid" and the capacity numbers show between twice and four times larger capacities of the fixer when a wash aid is part of the process." ...
    Rafal,

    Richard is correct about the commercial vs. "archival" standards. I'm not sure why Ilford says that a wash-aid will increase fixing capacity; I've really never seen convincing evidence that it can. What it can do, however, is help wash out compounds that might discolor more quickly. Take a look at this document
    http://www.ilfordphoto.com/Webfiles/...0218312091.pdf and look at the section on silver concentration starting on pg. 4 bottom left. That should explain everything.

    Personally, I think the information about fixers and capacities is more confusing than necessary and that the manufacturers are partly to blame for disseminating ambiguous and sometimes erroneous information. A wash-aid is largely sodium sulfite with a bit of buffering; it is not a fixer, will not change insoluble compounds to soluble and really cannot, therefore, increase fixer capacity as far as I can see. If someone has evidence to the contrary, I'd really like to see it... I don't seem to be able to find Ryuji Suzuki's document to read (which I would like to...). However, I do know that much of his research has been questioned by others on this forum much more knowledgeable than I, so I might tend to take his findings with a grain of salt till I saw some peer review. There may be a way that the sulfite helps "detach" some of the mordanted argentothiosulfates from the image silver, but I haven't seen a lot about this anywhere. Personally, I'd rather not rely on the wash aid to ensure proper fixing of my fiber-base prints... I'll continue to use two-bath fixation and err on the side of undershooting the capacity.

    Quote Originally Posted by Rafal Lukawiecki View Post
    Doremus, I hope I did not make it sounds like I was ever suggesting that KRST is a fixer. ... I am merely curious, however, if the presence of 3-5% of fresh ammonium thiosulfate in a working strength KRST ... would have a positive effect on the process of desorbing of the complex argentothiosulfates. I hope you will agree this is a valid question to ask, ...
    I don't know if the presence of ammonium thiosulfate in KRST helps in desorbing the argentothiosulfates... In fact, I'm not really sure why it is present in the toner to begin with. As you know, I replenish and reuse my KRST. I have gallon jugs that have been going for more than five years (more like 10). I'm sure that the ammonium thiosulfate in these toning solutions is as good as gone, but they still tone just fine (and don't have the annoying ammonia odor either). I'm curious as to what the ammonium thiosulfate is there for in the first place.

    And, I'm not a chemist either, although I have a few university-level chemistry classes behind me and I've been reading about and dealing with photo chemistry for some years now. I would always defer to Gerald Koch or PE or any of the other experts on this forum. My responses here are as much about learning as about giving information to others.

    My main point in my previous post, however, has less to to with chemistry and more to do with using time and resources wisely. It seems to me that you are spending an awful lot of time and effort trying to compound your own fixer and invent a new fixing process. Kodak (under Haist and others) and Ilford have done the research on fixers much more extensively and better than I could ever hope to do without dedicating a career to photochemistry and experimentation. I am happy to use their research and conclusions. There are a number of well-documented ways to fix and tone properly. Maybe you could spend your time better using one of those? Unless, of course, your goal is to explore photochemistry and fixer compounding. For me, I'll use my limited time to make prints using time-tested methods. I don't have time to spend re-inventing the wheel, so to speak.

    And, never any offense taken! You need not apologize to me about a lively exchange of ideas.

    Best,

    Doremus

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