This conversion chart has been constructed by comparing fired samples of Thompson's lead bearing and lead-free product lines.  The fired samples consisted of opaques fired directly on copper and transparents fired over clear (flux) on copper.  The matches are only approximations.  They are not exact matches, although in some cases the matches are very close to being exact.  There are a few omissions from the lead bearing line.  These numbers just did not have a very close lead-free counterpart.  However, most of these colors could be matched in lead-free by layering or mixing colors.