DMC and Crescent are two brands of embroidery floss, which is thread used mainly for embroidery or cross-stitch. The instructions on a pattern may list the colors you need in a particular brand. However, you might want to convert colors from one brand to another. DMC is a major brand and much easier to find than Crescent. Crescent floss is plain DMC floss that has been hand-dyed. Because Crescent floss is less common, finding a conversion chart from Crescent colors to DMC colors is difficult; however, you can match colors by eye.
Find a Crescent color chart or look online for a shop that sells Crescent floss. A commercial paper printout is better than looking at your monitor, however, because monitors all show colors slightly differently unless the monitor has been recently calibrated. You need a chart that shows samples of actual Crescent colors, preferably grouped by like color rather than listed alphabetically by name. Keep in mind, however, that Crescent colors are all hand-dyed and the actual colors will vary.
Find a DMC color chart. These are much more common than Crescent colors because DMC is a larger company. DMC uses numbers to designate its colors and the color numbers are arbitrary. There are more than 450 DMC colors, so look for a chart that groups the colors by like colors rather than by numerical order. DMC does not officially name its floss colors, so any names that might appear on a color chart from a certain group or company are useful but arbitrary.
Compare the colors on the Crescent chart to those on the DMC chart. It is impossible to get an exact match, so choose a color that seems close and appeals to your personal tastes. Write down the DMC number that most closely resembles the Crescent color you want to match.