The Color Checker SG has, as I understand it, a published LAB reference file—which was used to make the profile. In any event, this approach only works for reflective scans. While there may be some subtleties that this approach misses, the profile made this way is now performing superbly in day to day use. To date, it is the best profile I have had for my 10000XL, and if it has shortcomings they have not shown up so far. The gamut of the CCSG encompasses that of all the scans I have made with it.