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  1. #1

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    Decent (good enough) digital scale

    I only do occasional scratch mixing to experiment with things, so I can't justify spending serious $.

    This is for film developers in pretty small quantities. So I don't think I need a capacity of more than 200g. In fact 100g is probably fine. Resolution should be 0.01g.

    Is there anything accurate enough for $200 or less? There are some Ohaus scales around that price. I also found a company called MyWeigh. They make a small digital scale with 200g capacity and 0.01g resolution for under $100. But is it junk?

    Obviously for mixing photo chemicals I don't need some kind of crazy super precision thing. In fact if it were not for Phenidone resolution to 0.1g would be enough. But I don't want a piece of crap that's going to be materially wrong either.

    Thanks

  2. #2
    Hexavalent's Avatar
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    I purchased a small scale from Myweigh (can't remember the model offhand): 100 g capacity, .01 g resolution, less than $100. Quite satisfactory for my current emulsion-making needs.

    I would buy from them again, but a unit that can handle at least >200g to accommodate the added mass of a glass beaker etc.,

    The specs for scales can be misleading: resolution and accuracy are two different beasts. A scale with .01 gram 'resolution' may not be 'accurate' to 0.01 grams.
    - Ian

  3. #3
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    Michael, I'm on my 3rd balance, and I use a Kern School Balance EMB 200-2. It does up to 200g and its resolution is 0.01g, which is what you have asked for. I bought it for about €100. It is pretty good, realistically letting me have a precision of 0.1 with ease, and 0.04g with care. This one, like many in the under $400 range is of the design type known as "strain gauge". They either suffer from some "drift", which means that the reading slowly changes (in my case reading goes up about 0.01g every 10-20s), or they do not allow you to add small amounts, letting only larger added load to cause a displayed value to change. Of course, that second behaviour would be worse than the first for our needs, so I live with the slow drift, trying to be quick. The analytical design that uses electromagnets is more precise but much more expensive.

    I got mine from http://www.labunlimited.com/Online-S...-EMB200-2.html
    Rafal Lukawiecki
    See rafal.net | Read rafal.net/articles

  4. #4

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    I have some sort of ProScale, I think an LC50---one of the digital pocket scales that sell for a few tens of dollars, similar to the MyWeigh products (indeed I wouldn't be surprised if it the different brands all come from the same factory). It claims 0.01 g resolution, but for anything that fine I use a stock solution. In particular, I have a jar of phenidone in glycol and use that instead of relying on weighing out those tiny amounts of phenidone.

    For developer-in-small-batch uses, it's been absolutely fine for me. At the price point I don't believe it can possibly be as accurate as it claims, but I haven't seen that its limitations are a practical issue.

    -NT
    Nathan Tenny
    San Diego, CA, USA

    The lady of the house has to be a pretty swell sort of person to put up with the annoyance of a photographer.
    -The Little Technical Library, _Developing, Printing, And Enlarging_

  5. #5
    ath
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    Quote Originally Posted by Hexavalent View Post
    The specs for scales can be misleading: resolution and accuracy are two different beasts. A scale with .01 gram 'resolution' may not be 'accurate' to 0.01 grams.
    True, but one rarely (or never) needs to weigh 100g with an accuracy of 0.01g.
    Imagine a wodden folding yardstick, 2m long. The accuray is nowhere near 1mm over the whole length but you can use it without problem to measure if a plate is 3 or 4mm thick.

    Additionally most electronic balances (or, more precisely, all balances which measure the force of gravity of a mass) need to be calibrated at the place where they are used. Force of gravity changes quite a bit depending on your location. The good old beam balance avoids this by comparing the force of gravity of two masses.
    Last edited by ath; 06-01-2013 at 03:05 AM. Click to view previous post history.
    Regards,
    Andreas

  6. #6
    Mainecoonmaniac's Avatar
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    Check out meritline.com
    "Photography, like surfing, is an infinite process, a constantly evolving exploration of life."
    Aaron Chang

  7. #7

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    Reloading scales are relatively inexpensive. For example: http://www.amazon.com/Lee-Precision-...eloading+scale

    They typically measure in "grains", so conversion to grams will be required.

    It seems the small, inexpensive electronic scales are all over the map, with accuracy varying quite a bit from unit to unit.
    "Far more critical than what we know or do not know is what we do not want to know." - Eric Hoffer

  8. #8

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    Back many years ago, I picked up a triple beam balance for next to nothing at a police auction. I don't know if they are still available that way.....

  9. #9

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    Quote Originally Posted by Mark_S View Post
    Back many years ago, I picked up a triple beam balance for next to nothing at a police auction. I don't know if they are still available that way.....
    If you go this route, keep your receipt or clean the balance very well.

    Because you know what it's been used for.
    "Far more critical than what we know or do not know is what we do not want to know." - Eric Hoffer

  10. #10

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    Sensitivity (responsiveness to small changes in weight) can be slow with these pocket scales. I find repeatability is reasonable to say 0.1g. Digital balances are at best only good to half the last digit anyway. Mine is good enough, and at under $20 dollars delivered, I am not complaining.
    I feel, therefore I photograph.

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