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  1. #41

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    First, Crawley's Amateur Photographer article 13 Sept 08 states:
    " B
    Sodium L-Ascorbate 1.3g
    Phenidone 0.1g
    ADD TO 1000 ML OF A, DILUTED 1:9"
    There are some good deals on spectacles these days for those who missed it.

    Second,from the old safety data sheet I have ,FX-50,(which IIRC was diluted 1+1+8) would have had about 4 times as much of both potassium carbonate and sodium sulfite as FX-55,but there is no mention of what was the primary developing agent and no mention of bicarbonate so to make a comparison it would be necessary to guess both the primary developing agent and buffer,if any, in FX-50.

  2. #42

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    Quote Originally Posted by John Anders View Post
    I'm guessing that FX-55 is a close variant of Paterson's FX-50 which was formulated by Geoffrey Crawley. But in spite of its eco credentials and alleged qualities, it attracted unfavourable comment because of perceived lack of keeping quality and sudden death syndrome. After Paterson were forced to find a new manufacturer for their chemicals, they re-introduced Aculux (as Aculux 3) and FX-39, but not FX-50 (or Acutol). Although there have been rumours about a second coming for FX-50 in an improved version, I am guessing that Geoffrey Crawley has decided to release this formula now because that is not going to happen.
    It would be helpful to know how close FX-55 is to FX-50. For example, Crawley advocated an EI of 200 for Acros for standard development in FX-50.

    JA.
    Two things to say which might be helpful. Both follow on from your comments and give credence to your guess. In terms of speed increase Mr Crawley says of FX-55 that it can give between half a stop and one stop speed increase and he appears to have got round the sudden death syndrome by introducing a developer which is in two parts. Part A which has indefinite keeping qualities and Part B which is added at time of usage. The combined part A+B has only max 36 hours keeping quality and then only in a covered sealed container.

    pentaxuser

  3. #43

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    Quote Originally Posted by gainer View Post
    In case it's too difficult to figure out, here's a formula for a liquid FX55 part B with very long shelf life.

    1 gram phenidone
    10 grams TEA (it's liquid, but easier to measure by weight in such small amounts.)
    12 grams ascorbic acid, either L- or D-
    Glycol or glycerol to make 100 ml.
    Glycerol is more viscous.

    Use 10 ml of the above in place of 0.1 grams phenidone and 1.3 grams of sodium ascorbate.
    Paterson Photographic Ltd would be wise to consider some of your suggestions Patrick as it might lead to FX-50 being reintroduced with a significantly increased shelf life.

  4. #44

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    Some manufacturers produce one-shot viscous concentrates.IIRC DEA and DEA-Sulfur dioxide addition products produce alkalinity and sulfite.This has not been done with ascorbate.

  5. #45
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    DEA is diethanolamine and is of higher pH in water than TEA. It is used along with the sulfur dioxide in HC-110. Ascorbic acid can be added to HC-110. One could make a developer like HC-110 with ascorbic acid instead of hydroquinone and perhaps a little higher concentration of DEA than in HC-110. I would leave that to Kodak. I did show the result of adding ascorbic acid to HC-110 in an article in Photo Techniques some time ago. It is best if you want to try this to use the acid rather than the ascorbate, since the ascorbate does not dissolve well in DEA. The ascorbate will be formed between DEA and the ascorbic acid when the concentrate is diluted with water.
    Gadget Gainer

  6. #46

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    Six years after

    Six years after the OP, I made several tests with this developer.

    -- contraction and expansion are easy and predictable;
    -- grain is fine without being ultra-fine;
    -- sharpness is excellent (better than diluted D-76)
    -- mid-tone separation is very good.
    -- I did'nt noticed any significant speed increase (at least with Delta 100, Trix-X, Eastman XX).

    The only drawback is the preparation method.
    BTW, according to my thermometer, the addition of ascorbate + phenidone raise the temperature of a liter of A by 0,4° C.

    In conclusion, IMHO, FX55 is a really excellent developer.
    If anybody have a PDF of the original publication by Crawley, I'll would be glad to read it.

  7. #47

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    The problem with FX-50 was Fenton oxidation of the ascorbate ion. Under the right conditions the Fenton reaction can destroy all of the ascorbate ion in a matter of hours. Paterson tried to remedy the short shelf life of the developer concentrates by separating the developing agents from the alkalies. Unfortunately tis will not work. Any ascorbate based developer needs a chelating agent to complex any iron (III) and copper (II) ions present in all the chemicals used in the making of the developer concentrates(s). This also includes the water used. Look at the formula at this site for further information. The salicylic acid chelates the iron and the triethalamine chelates the copper. http://www.digitaltruth.com/data/ds-10.php

    Iron and copper are common contaminants of many chemicals such as sodium sulfite and sodium carbonate. The only way around the problem without using chelating agents is to add the ascorbate just before the working solution is used to develop film. Unlike the usual oxidation most people are familiar with Fenton oxidation will cause no color change in the solution. So there will be no warning that the developer has spoiled until it does not work. Paterson never realized what the real problem was and was therefore unable to solve the problem. They finally removed FX-50 from the market.
    Last edited by Gerald C Koch; 09-27-2014 at 11:03 PM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

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  8. #48
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    Very worthwhile read. Thank-you gentlemen.
    Get it right in the camera, the first time... My flickr
    Peter Carter

  9. #49

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    Quote Originally Posted by Gerald C Koch View Post
    The problem with FX-50 was Fenton oxidation of the ascorbate ion. Under the right conditions the Fenton reaction can destroy all of the ascorbate ion in a matter of hours. Paterson tried to remedy the short shelf life of the developer concentrates by separating the developing agents from the alkalies. Unfortunately tis will not work. Any ascorbate based developer needs a chelating agent to complex any iron (III) and copper (II) ions present in all the chemicals used in the making of the developer concentrates(s). This also includes the water used. Look at the formula at this site for further information. The salicylic acid chelates the iron and the triethalamine chelates the copper. http://www.digitaltruth.com/data/ds-10.php

    Iron and copper are common contaminants of many chemicals such as sodium sulfite and sodium carbonate. The only way around the problem without using chelating agents is to add the ascorbate just before the working solution is used to develop film. Unlike the usual oxidation most people are familiar with Fenton oxidation will cause no color change in the solution. So there will be no warning that the developer has spoiled until it does not work. Paterson never realized what the real problem was and was therefore unable to solve the problem. They finally removed FX-50 from the market.
    If this is true, Kodak could extend the working life of Xtol by adding a chelating agent but they have not.
    The shelf life of Xtol in part full bottles is at least 2 months:
    http://www.kodak.com/global/en/profe.../j109/j109.pdf

  10. #50
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    Quote Originally Posted by Alan Johnson View Post
    If this is true, Kodak could extend the working life of Xtol by adding a chelating agent but they have not.
    The shelf life of Xtol in part full bottles is at least 2 months:
    http://www.kodak.com/global/en/profe.../j109/j109.pdf
    Kodak uses DTPA as chelating agent in Xtol.
    Trying to be the best of whatever I am, even if what I am is no good.

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