spoon measurement

David, it my tests of using spoon (volume) vs weight, I have found as much as a 20% error in any given instance. In addition, I was looking through silverware information and found that spoon design can introduce quite a bit more error as there is no standard spoon it seems unless you get the generic variety from your local supplier.

PE

Better yet, weight it...I weigh everything..

Photo Engineer said:

David, it my tests of using spoon (volume) vs weight, I have found as much as a 20% error in any given instance. In addition, I was looking through silverware information and found that spoon design can introduce quite a bit more error as there is no standard spoon it seems unless you get the generic variety from your local supplier.

PE

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Very true. I assume the measurements given are for the standard kitchen measurement spoons. But there will still be significant variation because the chemicals do not always pack the same way and because you do not always fill the spoon the same way. For putting sulfite into fixer, I can use a teaspoon - the amount isn't that critical. But for developers, where I care about what the result will be, careful weighing is essential. Weston used teaspoon measures sometimes for his amidol print developers. If you look at his prints from that period, they are not all that consistent (beautiful, but not that consistent). But then, he was also developing by inspection using old materials (which were not that consistent, either). Today - weigh.

Photo Engineer said:

David, it my tests of using spoon (volume) vs weight, I have found as much as a 20% error in any given instance. In addition, I was looking through silverware information and found that spoon design can introduce quite a bit more error as there is no standard spoon it seems unless you get the generic variety from your local supplier.

PE

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First, Ron, I do not use the 'sloppy' spoon method. I use small, graduated cylinders which are precise in calibration. And, best to say this now: you have to tap the powder down: not like crazy, but a few times with moderation, in order to gain any consistency and to make a level top for the powder.

Theoretically, PE, you are correct and we all admit that. But my method does give more than acceptable results if you do it the way I state. I really doubt, if you do it my way. that you will get a 20% error or even close to that. I have been doing this for years. Spoons introduce unnecessary error and confusion (heaping or level?). Again, the ONLY reason I started this thread with 'spoons' is to reflect and sustain a collective familiarity. - David Lyga

RPC said:

Does this help?

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Of course this helps. It is what I had originally asked for. Thank you RPC.

But, alas, RPC, we are unable to scroll past 'S'. You have submitted a 'picture', not an Excel worksheet. - David Lyga

David Lyga said:

Of course this helps. It is what I had originally asked for. Thank you RPC.

But, alas, RPC, we are unable to scroll past 'S'. You have submitted a 'picture', not an Excel worksheet. - David Lyga

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I just sent you the one from Anchell, though there is only one "T" chemical in it.

David Lyga said:

Spoons introduce unnecessary error and confusion (heaping or level?).

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When cooking, this is my standard rule: All spoons are level unless the recipe dictates otherwise. So if a recipe states 1 teaspoon baking soda, I use one level teaspoon of it. This seems pretty reasonable for photography too, if one insists on using spoons instead of weighing the chemicals.

In high school and college chemistry class, we weighed everything unless it was a liquid, in which case it got measured in a graduated cylinder or beaker.

David Lyga said:

But, alas, RPC, we are unable to scroll past 'S'. You have submitted a 'picture', not an Excel worksheet. - David Lyga

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What you see, is all there is in the chart I got from somewhere, but don't remember where. If there was ever more to it, sorry, I don't have it. I've never used it; I weigh everything.

David;

I have gotten NaBr from two sources that varies in crystal habit. One is a fine powder and the other is coarse cubes. There is a HUGE difference in weight when one weighs an exact teaspoon of each. For one thing, it is hard to get a "level" teaspoon of large cubes, but easy to do this with a powder.

This leads us to grinding and cleaning up the residue.

PE