Different Amounts for Different Colors

Unlike the Cibacron F dyes (now sold as Novacron, or as Sabracron by ProChem), the Procion dyes are not standardized to a similar tinctoral strength per color. Even among the mostly undiluted single-hue Procion MX type dyes, some require more dye to get a similar intensity of color.

ProChem's approach is to use various amounts of dye for their color chips, online or included with their printed catalog, and specify how much dye is required to match the color they display. This gives you a general idea of whether to use more or less dye than the strength they indicate.

Dharma takes two different approaches. The first is a quick-to-use system of applying one asterisk to colors they think should be used at twice the strength (by volume) of unasterisked colors, and two asterisks to the colors that they think should be used at four times the strength. The second is a wonderfully detailed chart of dye yields, specifying OWG, ounces of dye per pound of fiber, and grams of dye per pound of fiber, for every one of the Procion MX type dyes they sell, to obtain a color intensity similar to the color chips in their catalog. Older versions of this chart included specific volume amounts, as well, but of course those measurements change with every dye lot, so they must have decided to no longer carry this added information, as it changed.