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  1. #21

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    Quote Originally Posted by Jeremy Moore
    I have a couple of questions about the dichromate method after Sandy's posting to this thread:

    http://www.apug.org/forums/showthrea...1867#post71867

    1. Can I avoid the mixing of potassium dichromate by buying the 2% bottle from Bostick and Sullivan and adding 3 drops of 2% instead of 1 drop of 5%?

    2. How often does the dichromate need to be added to the developer? Is this a one shot thing or over the course of a month will it need to be re-added?

    3. What else should I order from Bostick and Sullivan? I feel odd ordering something which will cost more to ship than the cost of the item ($2.48 for 25mL of 2%). I guess I'll wait until I have some extra cash and order some more palladium and ferric oxalate at the same time.
    1. Yes, but the bottle of 2% solution won't go far. Just bite the bullet and buy 100 or 200 grams of potassium dichromate. It will last forever in powder form, or in solution if you mix it with distilled water.

    2. Dichromate does not need to be re-added. All you need to do is top off your developer to replace what is used in processing with fresh developer, adding back dichromate as need.

    3. Palladium printing is very simple. All you need is ferric oxalate powder, potassium oxalate, sodium citrate or ammonium citrate developer, and sodium chloropalladite. You might also want to have on hand a small amount of oxalic acid and/or citric acid depending on which developer you settle on. And either Na2, dichromate or hydrogen peroxide (or other) depending on how you plan to control contrast.

    Sandy
    Last edited by sanking; 11-01-2004 at 04:59 PM. Click to view previous post history.

  2. #22
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    Quote Originally Posted by Jorge
    1.- Yes
    2.- you will have to determine that, I replenish the dichromate in my solutions every 800 sq inches.
    3.- Artcraft is a little bit cheaper.

    I dont know why you dont want to mix it, it is not as bad as it sounds. As I have been trying to say in many posts, mixing of chemicals, if done with care should not be any different than cooking. You keep the kitchen clean, you pick up what you spilled immediately and if you get it on you, you wash right away or change clothes. I ordered 200 gr of potassium dichromate, I still have a hole bunch after 3 years, so far I have not sprouted any extra arms..
    Jorge, I wanted to buy it pre-mixed because according to Bostick & Sullivan ordering it in powder form necessitates a hazardous chemical charge will probably be about 10x the cost of the actual chemical.
    Let's see what I've got in the magic trash can for Mateo!

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  3. #23
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    Quote Originally Posted by sanking
    1. Yes, but the bottle of 2% solution won't go far. Just bite the bullet and buy 100 or 200 grams of potassium dichromate. It will last forever in powder form, or in solution if you mix it with distilled water.

    Sandy
    If I don't need to re-add it, but just mix it in with my developer to top off why would I need so much? I am pretty sure that 100mL (~$3.50) should last me a couple of years if I'm only adding 1-3 drops/liter.
    Let's see what I've got in the magic trash can for Mateo!

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  4. #24

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    Dichromate

    Jeremy-I'll send you some for free-just PM me your address. Like Jorge said I also bought 5 LBS and it will last forever!
    Regards Peter

  5. #25

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    Quote Originally Posted by Jeremy Moore
    Jorge, I wanted to buy it pre-mixed because according to Bostick & Sullivan ordering it in powder form necessitates a hazardous chemical charge will probably be about 10x the cost of the actual chemical.
    not really, it depends on the amount. I bought it from them and I dont remember being outrageous, or I would not have bought it.

    As to replenishment, I have found that the dichromate does exhaust after repeated uses, even if you are not topping off with PO. I let my bottles go to about 3/4 before I refill with PO, and even before then I see I need to add dichromate after 800 sq inches or my prints starts loosing contrast. This makes sense from the chemistry point of view.

    But heck Peter S is offering to send you some, take him up on it.

  6. #26

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    Quote Originally Posted by sanking
    You might also want to have on hand a small amount of oxalic acid and/or citric acid depending on which developer you settle on. Sandy
    Sandy,

    I was glad to read that sodium citrate with dichromate can be used. I had read in Dick Arentz's book that only potassium oxalate can be used. I'd like to move from kallitype and try palladium with double coating as talked about on this forum.

    From your quote I am not sure about your reference to citric or oxalic acid. Can your explain further?

    phil

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