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  1. #21

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    Quote Originally Posted by Erik Prestmo View Post
    The yellow green is interesting: I mix this way, tonite I needed 1,5 litre for 3 tanks (0,5 litre each) I weigh out and mix 54 x 1,5 gram of soda, 16 x 1,5 gram of Vitamine C and 40 x 1,5 times coffee and dissolve each in a container of 0,5 litres of water.

    After all is dissolved I mix the soda with Vit-C (color change) and then add coffee to get 1,5 litres.

    I never noticed any color change when I dissolved soda and then added Vit-C crystals directly in the solution (the concentration of all chemicals would of course be lower in the total amount of water).
    Very curious, I can't think of an explanation of why you see a color change in one instance and not in the other.

    I have always used Arm and Hammer brand washing soda here in the US. The form most common in ths country is the monohydrate since it is the most stable form and less bulky. I wrote off to the company and they sent me literature on its purity which is about 98%. The main impurity is sodium chloride. This is to be expected due to the method of manufacture. There is a small amount of iron present. I would assume that other brands are similar.

    I use the washing soda for print developers. But for film developer I either buy photograde sodium carbonate or make it from sodium bicarbonate. The amount of iron impurity in the washing soda makes it problematic for ascorbate developers. However, since you make up developer just before use there should be no problem.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  2. #22

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    I will try mixing Soda, adding Vit C, KBR and coffe in that order and see if I can spot any color changes.

    Iron in the soda : In what way does that affect the ascorbate? You mean its a problem for ascorbate, not for ascorbic acid?

    I also use monohydrate, called Crystal soda here locally, its used for washing all of the house before Xmas!

    I use this stuff for film only, developed two rolls of FP4 that was somehow "forgotten" after being exposed in the early 1980's yesterday - the film looks like it was brand new! Excellent negatives!

    Only problem over here is finding Vitamine C, even in the health food stores - seems there's a movement afoot in that business, about Vitamine C being "too hard for the intestines" - they even refuse to order it!

  3. #23

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    I myself have just started with the caffenol developer. All of the ingredients I needed were easily found on eBay. At very little cost.
    http://cgi.ebay.com/Ascorbic-Acid-Vi...#ht_2390wt_907
    http://cgi.ebay.com/SODA-ASH-SODIUM-...ht_2362wt_1141
    Last edited by FM2N; 11-25-2010 at 10:55 AM. Click to view previous post history.

  4. #24
    guitstik's Avatar
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    Every time I have asked a pharmacist for ascorbic acid (vitamin C) they tell me to get the Fruit-Fresh. Apparently the amount of ascorbic acid in the FF is higher than they carry. The only other way to get a higher concentration of Vit C is to get it in an injection and that requires a prescription. You would not think that it would be that hard to get a hold of pure vit C.
    Thy heart -- thy heart! -- I wake and sigh,
    And sleep to dream till day
    Of the truth that gold can never buy
    Of the bawbles that it may.

    www.silverhalidephotography.com

  5. #25
    David William White's Avatar
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    The Photographer's Formulary has ascorbic acid for $11 for 100g. Don't know if that's out of your price range, but...
    Considerably AWOL at the present time...

    Archive/Blog: http://davidwilliamwhite.blogspot.com

  6. #26
    Nicholas Lindan's Avatar
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    Quote Originally Posted by guitstik View Post
    Every time I have asked a pharmacist for ascorbic acid (vitamin C) they tell me to get the Fruit-Fresh.
    I think you need a fresh pharmacist.

    Any good health food store should have Ascorbic Acid powder/Vitamin C crystals. If not then use the net:

    http://www.amazon.com/Ascorbic-Acid-...f=pd_sbs_hpc_1
    http://shop.ebay.com/?_from=R40&_trk...All-Categories

    Though, in the spirit of Cafenol, maybe the correct source for Ascrobic Acid is home made. Go out in the garden and start clipping rose hips - just right for harvest about now.
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  7. #27

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    Quote Originally Posted by Erik Prestmo View Post
    Iron in the soda : In what way does that affect the ascorbate? You mean its a problem for ascorbate, not for ascorbic acid?

    I also use monohydrate, called Crystal soda here locally, its used for washing all of the house before Xmas!

    Only problem over here is finding Vitamine C, even in the health food stores - seems there's a movement afoot in that business, about Vitamineor C being "too hard for the intestines" - they even refuse to order it!
    I can see where might be digestive problems for those taking megadoses but for those taking less than 1 gram a day there shouldn't be any problems. Perhaps teling the health food stores this will increase the availability.

    The term ascorbate can refer to either the ascorbate ion or ascorbuc acid which can be thought of as hydrogen ascorbate. When you dissolve ascorbic acid in a sodium carbonate solution you get ascorbate ions.

    Iron ions catalyse a particular form of oxidation called Fenton oxidation in the presence of ascorbate ion. The result is that the ascorbate is quickly destroyed. Developer can loss its effectiveness overnight. This was the cause of the sudden death syndrome reported with ascorbate developers like Xrol. Since you mix your developer immediately before use this shouldn't be a problem. But it can cause a problem when the developer is stored. The more iron impurity the faster the reaction. The oxidation products of ascorbic acid are colorless so there is no visual indication of any problem. Kodak, Ilford, Paterson, and other manufacturres now add a complexing agent to their developers to prevent this oxidation.

    Ryuji used a combination of triethanolamine and salicylic acid as complexing agents in his DS series of developers. He published 2 film and 2 paper formulas. Check his website (www.silver-grain.org) for a detailed description of the Fenton reaction. I have used a film and a paper developer from the series and they are very good. For those who have access to photochemicals like Dimezone or Metol I would recommend them.

    For those having difficulty finding ascorbic acid crystals, try to obtain Vitamin C in tablet form. They are usually 500 mg in ascorbic acid and have the advantage of being pre-weighed. You will have to filter out the insoluble binder after dissolving them. Another source would be sodium erythorbate (sodium isoascorbate). This isomer is somewhat more active as a developer than sodium ascorbate. Erythorbate is used as a food preservative for such things as sausages. I obtain mine from a spice company (Suttons Bay) for ~$7 a pound.
    Last edited by Gerald C Koch; 11-26-2010 at 10:12 AM. 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.

    ~Antoine de Saint-Exupery

  8. #28

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    Quote Originally Posted by guitstik View Post
    Every time I have asked a pharmacist for ascorbic acid (vitamin C) they tell me to get the Fruit-Fresh. Apparently the amount of ascorbic acid in the FF is higher than they carry. The only other way to get a higher concentration of Vit C is to get it in an injection and that requires a prescription. You would not think that it would be that hard to get a hold of pure vit C.
    This seems kind of bizarre. Have you tried your nearest hippie-health-food store (there's a Whole Foods in Memphis, if nothing closer), or a nutritional-supplements shop?

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    Nathan Tenny
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  9. #29

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    a pharmacists will be able to order it for you .. if need it local --
    it sounds like the pharmacy-tech you spoke with didn't want to deal
    so s/he sent you to the canning aisle.

    trader joe's has it in the supplements aisle,
    it is the cheapest i have found it in a health food or vitamin store
    and there is a t/j in nashville ... not sure if you are close to that, TN is a big place.

    john

  10. #30
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    I had almost decided to go with just straight caffenol instead of the "C" when I found a whole-foods store here in Memphis. I haven't had the opportunity to get by there yet but when I called and got prices and heard $15.99 for 8oz I had a stroke. I still need to get by there to check but....
    Thy heart -- thy heart! -- I wake and sigh,
    And sleep to dream till day
    Of the truth that gold can never buy
    Of the bawbles that it may.

    www.silverhalidephotography.com



 

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