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  1. #1

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    Mixing half of D-76 Powder

    Is it OK to mix half of a package of D76 - measured exactly on a scale -?
    Is the powder mixture uniform/consistent to allow this?
    Thanks in advance.

  2. #2
    Anscojohn's Avatar
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    Not a good idea. Your second paragraph alludes to the reason why. Best to mix it all, then put the stock in proper smaller bottles, filled completely, and tightly capped.
    John, Mount Vernon, Virginia USA

  3. #3
    Ian Grant's Avatar
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    This question keeps being asked. The dev keeps quite well in a full bottle it isn't worth the risk of trying to split it, it may not be homogeneous. It's definitely not advisable although some people do it.

    Ian

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    John and Ian: Thank you for the rapid response. You confirmed my suspicions.

  5. #5
    Vaughn's Avatar
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    The best way is to mix the gallon up, then split it into smaller bottles -- fill them to the very top with a good cap and they'll last a long time (6 months in a full bottle, two months in a half filled bottle...as per Kodak).

    Vaughn
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  6. #6

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    Renato: All powders that are mixtures are heterogeneous in nature, thusly there will be a difference in particles from the start of the mixture to the end of the mixture, solutions are all by nature homogeneous, which means the that they all have the same concentration and whatnot throughout, your best bet if you want to make up small volumes of chemicals is to get something like HC110 or PCTEA and mix it from syrup.

    Ben

  7. #7
    PhotoJim's Avatar
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    An idea to consider, if you prefer smaller quantities: you can make D-76 from scratch ingredients. The ingredients keep very well (for years, at least). You need an accurate scale and a little patience, but you can make precisely what you need, no more and no less, on demand.
    Jim MacKenzie - Regina, Saskatchewan, Canada

    A bunch of Nikons; Feds, Zorkis and a Kiev; Pentax 67-II (inherited from my deceased father-in-law); Bronica SQ-A; and a nice Shen Hao 4x5 field camera with 3 decent lenses that needs to be taken outside more. Oh, and as of mid-2012, one of those bodies we don't talk about here.

    Favourite film: do I need to pick only one?

  8. #8
    BetterSense's Avatar
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    I think the "Inhomogeneous powder" angle is silly. If you are worried about it, shake the bag up or pour the powder between to containers to mix it up. As long as you can at least somewhat precisely split the powder in half either by volume or weight, I wouldn't hesitate to do it at all. I've done it with Dektol.

    But they sell 1L bags, and the stuff keeps in bottles pretty well, and you can use a concentrated developer, so it doesn't even seem worth the effort to mix up only half.

  9. #9
    Vaughn's Avatar
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    Quote Originally Posted by BetterSense View Post
    ...or pour the powder between t(w)o containers to mix it up...I've done it with Dektol...
    Wear a very good dust mask if you do this! Metol powder in the lungs is not a good thing...a good way to get serious lung problems. Also, screwing up a few prints due to incorrectly mixed chemicals is one thing -- but doing the same with negatives is never a good thing.

    Vaughn
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  10. #10
    MattKing's Avatar
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    Quote Originally Posted by BetterSense View Post
    I think the "Inhomogeneous powder" angle is silly. If you are worried about it, shake the bag up or pour the powder between to containers to mix it up. As long as you can at least somewhat precisely split the powder in half either by volume or weight, I wouldn't hesitate to do it at all. I've done it with Dektol.
    For Dektol, it probably doesn't matter, because we tend to develop paper to completion. If print developer is either too active, or not active enough, we can see that, and reprint.

    For film development, there is no way to make sure that the powder is homogeneous, because different chemical components may have similar appearance, mass, and crystalline texture. You just cannot tell by looking.

    You don't want to have two batches of film developer where one batch is 10% more active than the other - unless of course you are developing by inspection .

    All it takes is one underdeveloped film, and any savings will be wasted.

    Matt

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