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  1. #1
    Murray Kelly's Avatar
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    Organic solvents in devlopers - beneficial?

    Re-reading the paper by Charnley tonight, I was struck with the idea that he claimed that FX-1 keeping quality was improved by adding isopropyl alcohol to the bath A.

    I cannot work out why the presence of an organic solvent at dilution with water would improve keeping qualities. Do the organic molecules of (say) metol selectively attract the disolved organics (like isopropyl alcohol) and become more resistant to oxidisation thereby?

    I have to say that I have FX-1 concentrate made up into glass ampoules 45 years ago that is still fully active but I would assume that that was due to the limited supply of oxygen above the liquid in the ampoule. I made it up with the isopropanol (terribly hard to get in 1961) and never questioned the addition at that time. It was in the formula and I never thought to ask 'why'.

    I have seen mention that acetone is added to developers to the strength of about 1 oz / quart but no no explanationis ever given. Maybe it is for some magical property? Could it be in fact, true?

    Would such water miscible organic solvents add extra longevity stock solutions?

    PE - can you cast any light on this?

    Murray,
    Brisbane.Oz

  2. #2

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    Quote Originally Posted by Murray Kelly View Post
    Re-reading the paper by Charnley tonight, I was struck with the idea that he claimed that FX-1 keeping quality was improved by adding isopropyl alcohol to the bath A.

    I cannot work out why the presence of an organic solvent at dilution with water would improve keeping qualities. Do the organic molecules of (say) metol selectively attract the disolved organics (like isopropyl alcohol) and become more resistant to oxidisation thereby?

    I have to say that I have FX-1 concentrate made up into glass ampoules 45 years ago that is still fully active but I would assume that that was due to the limited supply of oxygen above the liquid in the ampoule. I made it up with the isopropanol (terribly hard to get in 1961) and never questioned the addition at that time. It was in the formula and I never thought to ask 'why'.

    I have seen mention that acetone is added to developers to the strength of about 1 oz / quart but no no explanationis ever given. Maybe it is for some magical property? Could it be in fact, true?

    Would such water miscible organic solvents add extra longevity stock solutions?

    PE - can you cast any light on this?

    Murray,
    Brisbane.Oz
    Murray, I assume you refer to Geoffrey Crawley (inventor of FX-1). Crawley discusses the use of isopropanol to dissolve the Glycin in FX-2. See the BJP Annual 1970, pages 212,213.

    In my experience, Metol is not soluble in isopropanol.

    Metol and glycin are soluble in Triethanolamine (in my personal experience). The resultant stock solutions have remained active for over 3 years.
    Tom Hoskinson
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  3. #3
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    Tom is correct.

    IPA does nothing magic to developers to improve stability or activity as far as I know, but benzyl alcohol increases development in color developers. So do a number of other organic chemicals. Hydroxyl amine and other compounds are known to increase stability of color developers, but good old sulfite is the best all around stabilzing agent. TEA or PG both are good solvents and tend to exclude oxygen and preserve concentrates.

    PE

  4. #4
    Murray Kelly's Avatar
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    Thanks, Tom and PE. I couldn't believe that a small amount of IPA would make any difference and both of you have confirmed my conviction. I had been re-reading the BJP articles in the original copies from '61. I don't have access to the '70 Annual. Does he add it to the mixture to somehow improve solubility, or does he disolve the glycin separately as in making a stock solution? In the original paper the IPA was added to the bulk and was said to work in a very dilute amount.

    And, yes Tom, is was Crawley I meant. Thinking too much of the idea and not the source. Charnley is famous in my other field of that four letter word - work - the curse of the drinking classes.

    Whatever - thanks for the thoughts.

    Murray,
    Brisbane. Oz

    Quote Originally Posted by Tom Hoskinson View Post
    Murray, I assume you refer to Geoffrey Crawley (inventor of FX-1). Crawley discusses the use of isopropanol to dissolve the Glycin in FX-2. See the BJP Annual 1970, pages 212,213.

    In my experience, Metol is not soluble in isopropanol.

    Metol and glycin are soluble in Triethanolamine (in my personal experience). The resultant stock solutions have remained active for over 3 years.

  5. #5

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    Quote Originally Posted by Murray Kelly View Post
    Thanks, Tom and PE. I couldn't believe that a small amount of IPA would make any difference and both of you have confirmed my conviction. I had been re-reading the BJP articles in the original copies from '61. I don't have access to the '70 Annual. Does he add it to the mixture to somehow improve solubility, or does he disolve the glycin separately as in making a stock solution? In the original paper the IPA was added to the bulk and was said to work in a very dilute amount.

    And, yes Tom, is was Crawley I meant. Thinking too much of the idea and not the source. Charnley is famous in my other field of that four letter word - work - the curse of the drinking classes.

    Whatever - thanks for the thoughts.

    Murray,
    Brisbane. Oz
    Murray, In his instructions for mixing FX-2, Crawley wrote:

    "In 4oz of water, boiled for just 3 minutes, then cooled to 90F, dissolve a pinch of the sulphite, next the metol, then the rest of the sulphite and add the glycin. If the glycin remains as a yellowy suspension after 3 minutes mixing, add a pinch from the weighed carbonate (7.5 grams crystalline potassium carbonate) and restir, repeating the operation if it still fails to dissolve. Alternatively, replace .25 oz of the water with iso-propyl alcohol which will dissolve the glycin."

    1970 BJP Annual, page 213.

    Crawley's FX-2 Working Solution
    Metol----------------------------------0.25 gm
    Sodium Sulphite (anhyd)----------------3.5 gm
    Glycin----------------------------------0.75 gm
    Potassium Carbonate (crystalline)--------7.5 gm
    Pinacryptol Yellow 1:2000 solution--------3.5 ml
    Water-----------------------------------1.0 liter

    (Do not use Calgon, etc.)
    Tom Hoskinson
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    Everything is analog - even digital :D

  6. #6
    Murray Kelly's Avatar
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    Thanks again, Tom. I had a wry smile tho - how does one substitute 1/4 oz of the mixture without throwing out some of the stuff you need that's in there already? OK You just add it, I know. He must've known it worked - someone on his staff did the legwork and came up with the answer. Still it's only, what, 1/16th of the total volume? But who am I to argue? If it works, it works.
    What atracted my attention was the claimed keeping quality improvement (that's how I remember it).
    I was always of two minds about FX-2 vis a vis FX-1 anyway - I just wanted clarification on the point I raised.

    Murray
    Brisbane, Oz



 

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