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  1. #1

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    d-76 packaging - wrong amount?

    on my d-76 pouch of concentrated powder it says there is 14.6oz, but i measured 10oz. so what i did was put 5oz and treated it as though it was half of the package and mixed my developer accordingly (it says the package of 14.6oz will make 3.8L, so i just took half the package and made 1.9L). the negatives turned out normal (which would be 7.3oz), but what's up with that? does the powder get more dense with time or something? it may seem trivial as i just treated it in terms of percentage and it worked out fine, but if i used a different form of measuring it could have been horrible.

  2. #2

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    i also just mixed my xtol and it's the same deal - says 9.4oz but measured 6.5oz. as i look harder maybe i'm just an idiot as the beaker says "fl.oz", so i'm assuming fluid ounces are a different measurement than normal ounces? correct me if i'm wrong. i'm canadian, i work in mL and L.

  3. #3

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    Quote Originally Posted by jordanstarr View Post
    i also just mixed my xtol and it's the same deal - says 9.4oz but measured 6.5oz. as i look harder maybe i'm just an idiot as the beaker says "fl.oz", so i'm assuming fluid ounces are a different measurement than normal ounces? correct me if i'm wrong. i'm canadian, i work in mL and L.
    Think about it, they have to be. A fluid ounce is a volumetric measure, corresponding to the volume of an ounce of water: 20 oz to the pint (Americans use smaller pints of 16 fl. oz., but bigger fluid ounces, so an American pint is roughly 8/9 the size of a real pint).

    Now consider specific gravity. Alcohol (from memory) is 0.78, so one fluid ounce will weigh 0.78 oz, while mercury is 13.0 so a fluid ounce weighs 13 oz.

    Powdered developer chemicals sink, so an S.G. of 1.3 to 1.5 sounds about right, so 10 fl. oz. would be 13 to 15 oz. An odd idea, measuring powders in fl. oz., but unless I'm reading you wrong (which I may well be) I see no other possibility.

    Cheers,

    Roger

  4. #4
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    Think about it, they have to be. A fluid ounce is a volumetric measure, corresponding to the volume of an ounce of water: 20 oz to the pint (Americans use smaller pints of 16 fl. oz., but bigger fluid ounces, so an American pint is roughly 8/9 the size of a real pint).
    Well, at the risk of starting a flame war: there's a reason to use the metric system ;-)

    To confuse things even more: I just mixed a "small" bag of D-76 actually. That also states the contents in ounces, but it mixes 1 liter of developer, rather than some non-metric measure.
    I did not measure the weight of it, unfortunately.

    cheers,
    ./Niels

  5. #5

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    Quote Originally Posted by niels View Post
    Well, at the risk of starting a flame war: there's a reason to use the metric system ;-)
    Dear Niels,

    True enough. I can see a couple of real reasons to use imperial measure -- it's much harder to be an order of magnitude out, and a pint is a much more satisfying measure for beer than a half litre (and your beer goes cold if you order a whole litre, unless you're really thirsty) -- but the main reason that I still use them is that I was brought up with them and am used to them. My generation (I was 57 last week) has to make a bit of an effort to think in the metric system, at least outside the lab (and even there, I seem to recall that the MKS/CGS changeover was when I was at school), but I think it's an effort worth making.

    I can't see any excuse at all, except perhaps a desire to give short measure, for the short or wine gallon (3.96 l) instead of the imperial gallon (4.54 l). That'll get the flamers going!

    To return to the main point, though, yes, ounces-per-litre is pretty weird.

    Cheers,

    Roger

  6. #6
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    Also besides the point, but Roger, you are spot on about the beer. It was really satisfying to be able to order a pint while I was in the UK recently. It just feels right ;-)

    The Germans have a nice work-around for this. They use half-litre glasses, but one just orders a "big" beer.

    And I can definitely see your point about what one is used to. I lived in the US for a year, and the only thing I ever got used to were the length measures (inch, feet, yard) and a couple of simple volumes. Fluid ounces and weights, the different gallons, just confused the hell out of me.

    cheers,
    ./Niels

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    Roger, happy birthday!

  8. #8
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    There are "ounces" of weight and "fluid ounces" of volume. There are 16 ounces in a pound, and there are 32 fluid ounces in a quart, and four quarts in a gallon. Speaking colloquially, we don't usually specify "fluid" ounces when talking about volumes, because it is assumed that liquids are measured in fluid ounces, and solids and powders are measured by weight, at least when we talk about "ounces" of a solid or powder as opposed to cups or teaspoons.

    The "ounces" on the package should be weight, not volume. If you measured the volume of the powder in (fluid) ounces, it wouldn't likely correspond to the weight of the powder in ounces.

    Just to make life more confusing, precious metals are usually weighed in Troy ounces, and there are 12 of those to a pound.
    Last edited by David A. Goldfarb; 06-27-2007 at 05:40 AM. Click to view previous post history.
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  9. #9
    Ole
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    Some older developer recipes could well be written in Apothecarie's ounces, which is the same as a Troy ounce AFAIK.
    -- Ole Tjugen, Luddite Elitist
    Norway

  10. #10
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    Ah, one of the wonderful things about being an American is the ability to be totally schizophrenic in measurements - my print fixer formula for instance is 1-cup sodium thiosulfate, 20-mg sodium metabisulfite, and half-a-tray of water.
    juan

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