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  1. #21

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    Quote Originally Posted by Gerald C Koch View Post
    With the right amount of iron III all the ascorbate in a solution can be destroyed in an hour or so. It can be that fast.
    And that's why I started this thread: My idea was to add the ascorbate at the last minute.

    Here's a related idea: Add the Vitamin C as pills!
    You can buy 1000 mg Vitamin C pills that are actually powder in gelatin capsules. Here are examples:

    It's easy to pull gelatin capsules apart, and pour out the powder into your beaker. So the procedure for developing would be:

    1. Pour developer into beaker.
    2. Add contents of a couple 1000 mg Vitamin C pills, and stir until dissolved.
    3. Develop as usual.

    This avoids the inaccuracy of using teaspoons, and eliminates the need for a scale. Is this appealing?

    Mark Overton

  2. #22

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    Quote Originally Posted by albada View Post
    And that's why I started this thread: My idea was to add the ascorbate at the last minute.

    Here's a related idea: Add the Vitamin C as pills!
    You can buy 1000 mg Vitamin C pills that are actually powder in gelatin capsules. ... It's easy to pull gelatin capsules apart, and pour out the powder into your beaker. So the procedure for developing would be:

    1. Pour developer into beaker.
    2. Add contents of a couple 1000 mg Vitamin C pills, and stir until dissolved.
    3. Develop as usual.

    This avoids the inaccuracy of using teaspoons, and eliminates the need for a scale. Is this appealing?

    Mark Overton
    Hello Mark,

    I have used both vitamin C tablets and capsules as developer additives (I add ascorbic acid to PMK for expansions). Unfortunately, it's not so simple as "add contents ... stir until dissolved." All the vitamin C products I've tried also have binders and anti-caking ingredients (usually corn starch, etc.) which needs to be filtered out. I usually dissolve the powder from the capsule/tablet in a separate small amount of water and then filter that before adding it to the developer. Unless you can source some ascorbic acid in capsules that is in pure form, it may be more trouble than just weighing out the right amount of powder.

    Best,

    Doremus


    www.DoremusScudder.com

  3. #23

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    Interesting. So a couple of follow-ups since there are two types of purified water readily available to me (again, the only supposed problem I've ever encountered with purified water is with XTOL):

    Type 1- Label says: steam distilled (and ozonized), mineral salts 0PPM, Fluoride ions 0PPM

    Type 2 (the brand I've always used)- Label indicates: Treated by deionization and microfiltration (and ozonized), equivalent to distilled, mineral salts 5PPM, Fluoride ions 0PPM

    That's all the labels say so are either of these likely to weaken my XTOL upon mixing? I suppose it is impossible to answer without a detailed knowledge of the machinery used, but what are regular dummies like me supposed to do when Haist etc say used distilled water for ideal mixing? If the distilled water is no good, I guess I'm just S.O.L. since I can't very well start searching the globe for distilled water that has no Iron in it.

    Also, with respect to chelating, sequestering etc, I guess I would have thought Kodak included all the pertinent additives in packaged XTOL (which is what I use). I had always assumed since most packaged chemicals (even those containing ascorbate) are supposed to be suitable for use with tap water of varying quality, use of distilled water would make the stock solution even more stable if anything.

    Or perhaps I'm just worrying about nothing.


    Quote Originally Posted by Gerald C Koch View Post
    There are 3 ways to eliminate impurities in water

    1, Distillation, the oldest method. Water is vaporized, leaving the impurities behind, then allowed to cool using a condenser to form liquid water again. Traditionally a copper condensor was used for its large heat transfer capabilrty. If a metal condensor or catch container is made of metal then the water may become contaminated with metal ions. A particular problem is with copper. Even ordinary glas is a problem in preparing water for conductivity experimnts. The sodium in ordinary glass leachs out. Only fused silica equipment can be used.

    2 De-ionization, the water is passed throught a mixed resin ion exchange column. Metal ions are replaced with hydrogen ions and anions with hydroxide ions. The hydrogen and hydroxide ions combin to form water.

    3 Reverse osmosis, water under great pressure is forced through a semipermeable barrier. Large ions cannot pass through leaving, in theory, pure water.

    Iron and copper are common contaminants of the chemicals used for making developers. The wrorst offenders are probably sodium sulfite and sodium carbonate. So just using purified water may not help. A chelating agent is the best way to insure the storage life of ascorbate developers. Salicylic acid chelates iron and TEA does the same for copper.

    With the right amount of iron III all the ascorbate in a solution can be destroyed in an hour or so. It can be that fast.

  4. #24

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    Quote Originally Posted by Doremus Scudder View Post
    Hello Mark,
    I have used both vitamin C tablets and capsules as developer additives (I add ascorbic acid to PMK for expansions). Unfortunately, it's not so simple as "add contents ... stir until dissolved." All the vitamin C products I've tried also have binders and anti-caking ingredients (usually corn starch, etc.) which needs to be filtered out. I usually dissolve the powder from the capsule/tablet in a separate small amount of water and then filter that before adding it to the developer. Unless you can source some ascorbic acid in capsules that is in pure form, it may be more trouble than just weighing out the right amount of powder.
    Best,
    Doremus
    www.DoremusScudder.com
    Your posting made me take a closer look at the links I provided yesterday. Of the two makers of capsules, one includes 20 mg of ascorbyl palmitate, which Wikipedia says is only slightly water-soluble. The other is "Pure Ascorbic Acid" by Thorne Research, and its ingredients-list says it's indeed pure. But having only one brand of suitable capsules available is risky. A google search for "pure ascorbic acid" turns up several vendors of powders, so it's prudent to stay with powder as you suggested.

    Mark Overton

  5. #25

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    In pharmacy that used to be called stricken or struck measure. A heaping measure was struck level with a card.

    Remarkably repeatable.

    Best regards,

    /Clay

  6. #26
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    Quote Originally Posted by albada View Post
    Your posting made me take a closer look at the links I provided yesterday. Of the two makers of capsules, one includes 20 mg of ascorbyl palmitate, which Wikipedia says is only slightly water-soluble. The other is "Pure Ascorbic Acid" by Thorne Research, and its ingredients-list says it's indeed pure. But having only one brand of suitable capsules available is risky. A google search for "pure ascorbic acid" turns up several vendors of powders, so it's prudent to stay with powder as you suggested.

    Mark Overton
    Trader Joe's sells pure ascorbic acid powder in one pound jars for $11.99 in the vitamin section. I've used it for making vitamin C based paper developers. It works quite well.
    When the chips are down,

    The buffalo is empty!!!



  7. #27

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    Quote Originally Posted by Zathras View Post
    Trader Joe's sells pure ascorbic acid powder in one pound jars for $11.99 in the vitamin section. I've used it for making vitamin C based paper developers. It works quite well.
    You guys will like this. I made 6 stricken 1/2-teaspoon measurements of four brands of vitamin C powder, 24 weighings in all.
    The maximum deviation from the average weight was only 4%! The typical variation was under 2%.
    The average weight was 2.33 g.
    As Clay said, "remarkably repeatable". Clay, thanks for describing struck/stricken volume measurements. I'd never heard of that.

    The four brands were: Solaray, Jimbo's store brand, Photographers' Formulary and The Chemistry Store. And I drove by a Trader Joe's this afternoon on my way to Jimbo's to buy some AA, but hadn't read Zathras' posting yet so I didn't know. Sigh.

    My 1/2 teaspoon is marked "2.5 ml", and my teaspoon is marked "5 ml". Not all teaspoons follow the 5 ml standard, so check the size.
    Here was my exact procedure:
    1. Scoop out a heaping 1/2-teaspoon of ascorbic acid powder.
    2. Firmly press the spoon up against the bottom of a glass beaker.
    3. Scrape the spoon level
    4. Pour into a cup and weigh.

    I'm surprised at how well this works. "Remarkably repeatable" indeed.

    Mark Overton

  8. #28

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    They didn't normally compress the heaping measure first. Poured a small bowl full, then just dipped
    and struck it off clean.
    Best regards,
    /Clay
    Last edited by Clay2; 03-31-2013 at 12:57 AM. Click to view previous post history. Reason: spelling

  9. #29

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    Quote Originally Posted by Clay2 View Post
    They didn't normally compress the heaping measure first. Poured a small bowl full, then just dipped
    and struck it off clean.
    Best regards,
    /Clay
    I first tried this without compressing, and although measurements were repeatable enough, ratios of values from my 1/4-, 1/2- and 1-teaspoon spoons were farther from 2.0 than I liked. Also, tapping the spoon before striking would cause the powder to compact some, reducing repeatability. Compressing fixed both.

    Mark

  10. #30

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    Yes, that's why I got an Ohaus triple-beam balance, ha!

    Normally the uncompressed measure was good enough for me with very fine powders.

    Best regards,

    /Clay

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