Hi Mike, You wrote: "I am not simulating on an Inkjet, I am using the actual printing papers on an Indigo. Is there a correct way as a rule of thumb?" In this case, I would use M1 measurement mode (uvIncluded-D50 simulation). This should get you closer to correct numbers. As Roger pointed out the GRACoL Uncoated 2013 profile is based upon M1 measurement data. The problem here, of course, is the M1 mode itself. The specification, like all ISO specs, does not really provide guidance about conformance metrics and in recent test data that I saw, there was a fairly wide range of "opinions" between different families of instruments about the correct M1 response. The best case is where you use the same instrument on both sides of the process, but this often not the case. As you mentioned, you use an ISIS to build the profile. You can build an M1 profile using the X-rite i1Publish and the ISIS. To certify a color you should use an instrument like the i1ProII which has a very similar M1 condition. The M1 measurement condition will continue to be an issue, until with have a method of certification. Regards, Tom Lianza President Sequel Color Science and Instrumentation. On Dec 5, 2013, at 5:00 AM, colorsync-users-request@lists.apple.com wrote: