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Thread: Ratio question

  1. #1

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    I'm in the process of switching from Kodak chemicals to Arista chmicals (film & paper) and I've been out of the darkroom for 6 years.

    Here' where I need some help: 32 oz concentrate makes 2.5 gal which dilutes 1:9

    How do you figure this to get 1 gal?

    BTW: This is for all Arista chemistry.

    Thanks
    Chazz




  2. #2

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    9.6 oz will make a gallon.

    2.5 gal = 320 oz

    320/32 = 10

    so your dilution is 1:10

    then you measure 9.6 oz to 96 oz of water.

    if you want to make an exact gallon then measure 8.8 to 88 oz of water.

    Yes, yes I know the end result would be 96.8 oz, but is close enough for goverment work....no?

    BTW I should mention this is to go from your concentrated solution to your stock solution. I guess you then dilute the stock solution 1:9 to get the working solution. If you want to make a working solution from the concentrated solution you have to make a 1% solution which would be 1oz for for 99 oz of water.




  3. #3

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    Chazz,

    this is a good Question. For a Chemis, 1:1 means "stock solution", i.e. one part of solution A becomes one Part of solution B. 1:9 means one part Solution A becomes nine parts Solution B. In photography, however, 1:1 sometimes means 1+1. If you do not have an example in a manual, you'll have to make a guess. In your case, 1:9 most probably means 1+9, because it is a more convenient and thus more usual form. In this case take 1/10th of a gallon stock solution and fill it up to one gallon.

  4. #4

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    First you should all switch to metric-) 320oz for 2.5 gallons is sure to confuse us who grew up with imperial gallons.

    I don't think Jorge's math is right. What you know is 1 part is 32oz. 9parts is therefore 32x9. The total being 320. 1 gallon is what 128oz in the US?? therefore 1part would be 12.8 oz the rest would be water.

    This is the same thing Tschmid said.

    The easy thing would have been to divide 32oz by 2.5.

  5. #5

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    </span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Robert @ Dec 22 2002, 02:26 PM)</td></tr><tr><td id='QUOTE'>The easy thing would have been to divide 32oz by 2.5.</td></tr></table><span id='postcolor'>
    In this case, I misunderstood Chazz. Is the result already diluted 1:9? I thought that 32 oz make 2,5 gal stock solution which have to be diluted "1:9" and that he needs 1 gallon working solution.

    BTW: I&#39;m from Coninental Europe and I don&#39;t even know which gallons are which :-)

  6. #6

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    Sep 2002
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    If I understand he has a 32oz container [1 US quart] and it makes 2.5US gallons [10 quarts]. So you need to add enough water or 9quarts. 1:9-) If he wants to make 1 gallon instead of 2.5 then divede the 32oz by 2.5 and add enough water to that to make 1 gallon.

  7. #7

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    Jan 2003
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    I think you&#39;ve been helped with the ratio question, but If your looking for new chemicals that are easy to mix and cheap, I&#39;d recomend Sprint if they&#39;re available to you. I&#39;ve been using them for almost 2 years and love them. Whats nice is that the bottle explains EVERYTHING (even how to use the dilution ratio).

  8. #8

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    Sep 2002
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    Chazz- If a 1:9 dilution is what you need, divide the 128 oz. in a gallon by 10. That means you add 12.8 oz. of concentrate to water to make a gallon. Yes?



 

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