A Valdani thread conversion chart is a chart that shows the colors of Valdani-brand threads that are equivalent to other brands of threads. Valdani.com's chart, as of October 2015, covers conversions for Weeks Dye Works, The Gentle Art and Needle Necessities brands.
Each thread color has an alphanumeric reference code to distinguish which of many shades of green or rose is the one in question. For a pattern calling for 7025 for a thread by The Gentle Art, the chart gives the equivalent Valdani color as M49.
Valdani threads are hand dyed with lead-free dyes and are colorfast, meaning the colors do not leach out or fade in the wash. The company makes over 450 colors and guarantees its threads.
Colors vary from dye lot to dye lot, though Valdani's dyers minimize this as much as possible. Factors beyond control include the original shade of the raw cotton or other thread material, the temperature outside and the weather on the day the lot is dyed.
Valdani makes solid-color and variegated threads in cotton spools for quilting and sewing; perle cotton for embroidery, crochet, rug-hooking and other needlecrafts; cotton floss and ArtSilk rayon floss for PunchNeedle and embroidery. Luxury silk floss, pearl silk and 100 percent virgin Australian wool are also available.