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Thread: Home RA-4

  1. #11
    hrst's Avatar
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    The idea in replenishment is that the optimal tank solution has a specific amount of active developing agent, specific pH and specific amount of halides. When you process paper, it releases halides from the paper and eats up some developing agent. "Replenisher" is a special developer solution that has little or no halides and more developing agent than tank solution. Then, as you add this replenisher into used tank solution, it stays at correct levels. But again, when you make a new tank, you can't use just replenisher but you need a tank solution. To make it easy, tank solution can be obtained by mixing replenisher and "starter". This information applies to all "replenished" processes.

    So, simply put, if you use just replenisher as a new tank solution without a starter, you get too active developer with too little restrainer. This, again, is general information that applies to every replenished process.

    PE has suggested that you don't need to use any starter with these RA-4 chemicals when you process at room temperature. You get great results that way. This is specific to this process and at room temp. I don't know if you need to use starter at higher temperatures. Maybe, maybe not. Probably you will get higher contrast or shorter processing time if you omit the starter.

  2. #12

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    There is a colour shift between the Kodak chems used at 20 C and at normal temp. I'm not sure if this is due to the temp or to no starter solution, or a combination of both. I just use them as basicly one shot with drums at 20-22C and 2 min processing time, the process is very repeatable. I haven't tried the normal temp for processing yet, and I don't even see a need to try it.

  3. #13

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    Quote Originally Posted by perkeleellinen View Post
    These must be either discontinued or not available in the US.

    Can someone point me to the exact Kodak developer and bleach/fix I need, preferably through part number or Adorama links? I will be doing room temp tray development, as I need to keep the Nova for my b/w printing. Thanks.

  4. #14
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    --Nicholas Andre

  5. #15

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    Quote Originally Posted by tiberiustibz View Post
    Bingo! Thanks. Can the concentrates be mixed partially? 10 liters is a lot to store.

  6. #16

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    Yes, use 1/10 of each bottle to mix one liter of working solution, and PURGE the air from the factory packaging before you close it back up. It was packed with an inert gas at the factory.

  7. #17

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    Quote Originally Posted by Bob-D659 View Post
    Yes, use 1/10 of each bottle to mix one liter of working solution, and PURGE the air from the factory packaging before you close it back up. It was packed with an inert gas at the factory.
    Thanks. I noticed that the Protectan spray is no longer available. What do you recommend for purging the air? I was also considering picking up a couple of those Arkay floating lid tanks, but they're kinda pricey.

  8. #18

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    Ronsonol butane is readily available, it is also flammable just like Protectan, which is/was a mix of butane and propane. A large cylinder of nitrogen, a can of canned air(R134A type), google will find the CAS number for the chemical that is R134A. Then you just look at the ingredients. There is a huge number of posts here on about purging air from bottles. The newer canned air with a stink added might work, it is somewhat flammable as well.

  9. #19
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    Don't use air dusters. Terrible reactions with my chemicals for some reason, the concentrate absorbed most of the air. Rather weird. Stick with Nitrogen or Butane or other known inert gasses.

    Developer Bottles A and C have 500 mL and B has 222 mL. If you mix 50-22.2-50 starting with 800 mL of water and adding up to one liter than you should be good. Stir for a minute between the addition of each concentrate. I usually mix up a gallon at a time.
    --Nicholas Andre

  10. #20

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    Thanks. So I'm looking for just regular ol' Ronsonol butane spray from the tobacco shop? I can just spray that in the bottle for a few seconds and cap it quickly? I've never done this before.

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