This test is also useful when changing to a new lot of dyestuff to determine the degree of error that will be introduced when the new lot is used in the lab or in production. In most cases, variations between predicted and actual formulas are consistent within shade families and among particular dye combinations. This means that the first lab dyeing based on a modified prediction will be much closer to the target color than a formula based only on primary data. This process works well if the materials being dyed are consistent for an extended period of time. Application of this technology can significantly reduce the number of lab dyeings required to match new shades.
Many companies choose to use primaries provided by dye manufacturers.
This data is usually very consistent and offers a way for a lab to immediately begin shade matching or to evaluate a new dye or family of dyes. The dye manufacturer's primaries are usually available on a computer diskette in a form suitable for a large number of color matching programs. Although these primaries are usually very consistent when evaluated using the techniques discussed earlier, this does not guarantee that the formulas predicted will be accurate. This is caused by the use of different materials, different chemicals, different equipment and dyeing procedures, and even by different water supply. This does not mean that the supplier primaries cannot be useful, it simply means that the initial computer predictions will not be as accurate as ones based on primaries dyed in the lab's own environment.