With papers changing the way they are; most do not fall within the tolerances specified in 12647-2. I like this idea of the Substrate Calculator. My question is this. Let's say we proof to GRACoL tolerances on a paper that is within the specification. We now get a #1 or #2 paper that is out of spec. I use the calculator, create a new CGATS file and create a new ICC Profile. I use CGS ORIS Color Tuner and hone in my proofing device (Indigo press) to within tolerance and proof my files/images on the "new" paper. What have I achieved. I have created a proof that the printer may have an easier time "matching"; but can I say that this proof adheres to GRACoL specifications? If you were to read the 12647 color bar it would pass only if I have the proper dataset loaded to compare to using software such as ORIS Certified Proof. Someone else checking my proof to GRACoL would say it "fails" because they would be comparing to the "original GRACoL". What exactly have I accomplished and how can it be classified as a specification. Mike Stewart