To be honest, I do not usually weigh out my dyes, because reproducibility is not usually what I'm after, and it is easier to avoid getting dye dust into the air if I'm not weighing. When my energy is very limited I'm happy enough to be surprised by the colors I get, but sometimes I need to keep better records, which requires weighing. When I need to weigh dyes out, I have a nice little balance scale that measures 1 to 100 grams that I usually use for dyes. When I can't find that one, I use a larger heavy beam balance that I got from a lab that was closing. Carol Soderlund says to get a scale that weighs 1 to around 400 grams with a readability of 0.1 grams. Here's one that looks good to me (I haven't tried it):
http://www.rightonscales.com/web/120z.htmDon't put your dye directly on the scale. You don't want to have to clean it. Use some sort of paper or something to put the dye onto, on the scale. You need to cut out pieces of waxed paper, or get some sort of disposable plastic container. Lids from yogurt containers would be good if you go through a lot of that, for example. Dye will stick to plain paper, if the weather is humid enough. Some scales will let you 'tare'; the weight, which is to say, rezero after you put your weighing paper on the scale. That saves some thinking and is a great idea. Otherwise you have to subtract the weight of the paper from the final weight, which is the weight of the dye plus paper.
It's impossible to work with the customary measurements of ounces and pounds, fluid ounces and pints. It's much easier to work if you convert everything to metric, even if you rarely use metric. A calculator is handy to have for this. Most measuring cups these days have metric volume marked on one side and customary US measurements on the other. One cup is about 250 ml, two cups is 500 ml. Kitchen measuring cups are not as reliable as graduated cylinders used to measure volume in a lab–sometimes the lines on the side are a little off–but if you always use the same one your results should be pretty close.
Weight of goods is very easy to calculate. If your fabric weighs half a pound, that's half of 454 grams, or about 225 grams. If you want 6% OWG (I have never figured out why they include the intial for "on" in that acronym), you want 6/100 of this, or 6 times 225 divided by 100, which works out to about thirteen and a half grams. Or, you can measure out whatever amount you want to use with a spoon, plop it on the scale, and just write down how much it weighs and how much your fabric weighed, and make a note also of how many cups of water you used, as well as a note of the room temperature. Then you can always figure it all out later if you want to repeat your results exactly.
Linda Knutsen's book
Synthetic Dyes for Natural Fibers has a chapter on how to use the metric system to work with dye. It's well worth buying a used copy if you can get one for under $25, which is often possible.
The Jaquard Procion MX color mixing table is based on volume measurements, using teaspoons, but that means that it will not always work as expected. One batch of dye will be fluffier than another, so you get less dye in a given spoonful–sometimes only half as much! All other mixing guides are based on weight because that is more meaningful. A standard strength dye like we use will always be the same strength per weight, but can vary a lot by volume, from one manufacturing batch to another.
Paula
