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  1. #11
    Photo Engineer's Avatar
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    It was said above. Fixer is fixer.

    It is always a good idea to use one fixer for film and another for paper. The reasons are several.

    1. Film has different chemicals in it, and it may affect the rate of fixing of paper, and the final image quality.

    2. Film has more silver halide and therefore needs a more concentrated fix solution.

    3. Paper has less silver haldide and if you use film fix for paper you are over fixing and just wasting fix and requiring more efficient wash than you should.

    Therefore, the same fix chemistry is good for film and paper, but at different dilutions. So, the same fix should generally not be used for film and paper for that reason and the others listed above.

    It should not hurt or affect image quality to mix film and paper in the same fix if you adjust fix and wash times accordingly and keep track of the exhaustion level of the fix based on throughput of all materials.

    PE

  2. #12

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    Quote Originally Posted by gnashings
    Thank you so much for all the input - I am quite proud that a lot of it goes along the lines of what I suspected (better contrast?) - it was the first photo forum that I found, and while it does have some great people willing to help, I find that, like in the rest of the world, film/chemistry people are treated as a nuisance to some extent.
    A lot of the folks here took the time to say :"hey, I'm not sure" - which is great, and so much more than I got there.

    The reason I was looking around is that I suspect that the batch of Kodak fixer I mixed from powder has gone bad, or is not as potent as it should. Reason for that is, my prints started going pink (even after fanatical washing), and leaving in fresh fixer (never re-used) for at least the long end of manufac. recomendations...

    So I started looking around for reasons, remedies - I wanted to not know where my mistakes were to be found...

    Thanks again for all the input - 99 % of the time I log on and do not post, just read, read, read, read... So much knowledge here! Its wonderful!

    It's a good idea to get some Edwal Hypo Check, or similar. Just a drop in the fixer and it will turn milky white when the fix is exhausted. You can also go a cheap route; take the leader from the film ( you cut it off anyway) and throw it in the fix. Give it a good swish and it should clear in about 1 minute. This mean your fix is still good.

  3. #13
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    You should always use separate batches of fixer. Mix up one batch for film and another for paper. This is especially critical with ammonium thiosulfate based (rapid) fixers. Here's why:

    Modern films contain a substantial amount of silver iodide. Of the silver halides, iodide is the most difficult to remove from an emulsion. For this reason, fixers used with film tend to exhaust faster. So if a fixer that has been used for film is then used on paper, the prints may not be completely fixed.

    Complete fixation for prints is particularly important as the silver filaments that make up the image tend to be much smaller in a print than in a film. They are thus more prone to being attacked by atmospheric pollutants such as sulfur, which may cause image deterioration.

  4. #14
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    DOH! :o
    Glad I read this post. Looks like I'll have to mix up some more (at a greater dilution) when printing next.

  5. #15
    Ole
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    Quote Originally Posted by Photo Engineer
    It was said above. Fixer is fixer.

    It is always a good idea to use one fixer for film and another for paper. The reasons are several.
    Correct.

    Quote Originally Posted by Photo Engineer
    1. Film has different chemicals in it, and it may affect the rate of fixing of paper, and the final image quality.
    The main concern is the sensitising and antihalation dyes, which may make a delayed appearance in the prints. It's generally worse to get paper fibers in the film emulsion.
    Quote Originally Posted by Photo Engineer
    2. Film has more silver halide and therefore needs a more concentrated fix solution.
    No. All film is not alike, nor is all paper. Some papers contain significantly more silver than some films.
    Quote Originally Posted by Photo Engineer
    3. Paper has less silver haldide and if you use film fix for paper you are over fixing and just wasting fix and requiring more efficient wash than you should.
    See above. There is also some silver iodide in most papers, which takes a lot more fixing than bromide. Most films contain a little, the "T-grain" films are said to contain more, and Bergger Art Contact paper contains even more iodide than that.
    Quote Originally Posted by Photo Engineer
    Therefore, the same fix chemistry is good for film and paper, but at different dilutions. So, the same fix should generally not be used for film and paper for that reason and the others listed above.

    It should not hurt or affect image quality to mix film and paper in the same fix if you adjust fix and wash times accordingly and keep track of the exhaustion level of the fix based on throughput of all materials.

    PE
    I use the same mix at the same dilution for both film and paper, but I'm careful about not using the same bottle. At least most of the time.
    -- Ole Tjugen, Luddite Elitist
    Norway

  6. #16
    Photo Engineer's Avatar
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    Ole, I would like to add a few comments.

    I have never seen a camera film with less silver than any photographic paper product. Transmission based products require a lot more silver to get a maximum density of about 3.0 than reflection based products need to get to about 2.0.

    Also, print paper emulsions are generally chlorobromides, chlorobromoiodides, or chloroiodides. Films are almost always bromoiodides with the iodide generally being above 1% and sometimes up to 5%, with the level being higher in high speed films. Papers, if they have iodide, generally contain it at less than 2%. Fix can be dependant on iodide content. Papers sometimes contain toning chemicals to adjust the tone of the silver image and this can affect fixing rate.

    I hesitated to get so technical, but thought it might be useful to expand on my previous post in light of your excellent comments.

    I especially liked the comment you made about paper fibres getting into the fixer. I never considered that in my work, but then I use separate fixers anyhow so never saw the problem.

    Also, the dyes in film. Another good comment. I always prewet my films, and that rinses out a lot of them, but there are always some that can get into the fix. Very good point.

    PE

  7. #17
    Ole
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    PE, I assume you don't use Bergger's more "esoteric" papers. I sometimes do, and they are way out of the ordinary when it comes to composition and halide content

    The Art Classic Contact especially is a chloroiodide paper which really kills the fixer faster than film.
    -- Ole Tjugen, Luddite Elitist
    Norway

  8. #18
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    Ole, no, I don't use Bergger's papers. I suspect that the Kodak Polycontrast IV is a chloroiodide as well. It fixes more slowly than most other papers.

    You can control speed and contrast in a pure chloride emulsion by use of iodide, at the expense of fix rate and development rate, not to say what it does to the maxium achievable density.

    If you can get a copy, read the article by Dorsey Dickerson in the latest Photographic Techniques magazine regarding the maximum density in papers, and silver rich papers. It is quite interesting.

    Bergger is probably doing something fancy to get the tone they want. If it exhausts the fix that fast, then I would prefer not to use it. I use Ilford and Luminos papers.

    PE

  9. #19
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    Quote Originally Posted by rogueish
    DOH! :o
    Glad I read this post. Looks like I'll have to mix up some more (at a greater dilution) when printing next.
    According to my reading (Ilford recommendations amongst others) you are better using the paper fix at film strength, thereby allowing the paper to be in the fixer for a shorter time, resulting in less fixer being absorbed into the paper's fibres.

    As a general note, Tetenal produce test papers that measure the silver content and ph of the fixer on each strip - I use one of these at the start of each session and discard the fixer as necessary. Worth using for peace of mind...

    I did read somewhere that the old "see how long it takes to clear a piece of film and dump the fixer when the time doubles (or when it reaches 50% increase to be extra safe)" test is not reliable; something about chemical buildup in the fixer causing a problem even though the clearing time seems OK, but I can't remember the details. Any one got any facts or did I dream it? ...

    Cheers, Bob.

  10. #20
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    Bob;

    I find it easy to determine clearing time with film, but rather hard to do with paper. I find this method of judging fixer quality relatively good for film as a result but nearly useless for paper. I use the silver sulfide test for judging retained silver in papers. I use the silver nitrate test for retained hypo. Both have problems, but are moderately useful.

    There is a test solution of potassium iodide which is used to determine if your fixer is exhausted. A drop of this should stay clear or slightly cloudy when added to the fixer if it is good, but it will form a heavy yellow precipitate in exhausted fix. I find this test is only fair and depends on the type of fix.

    As far as using concentrated fix to prevent penetration into the fibres from less fix time, consider that the concentration gradient is higher with the concentrated fix. Therefore, you might end up chasing your tail, I really don't know. I wonder, do they offer any proofs that this works?

    PE

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