Actually, Graham, my original question (going back to October 20th), which hasn't been answered, was based on these commands here: targen -v -d2 -G -f100 iPFTest copy iPFTest.ti1 iPFRef.ti1 printtarg -v -r -ii1 -a1.0 -T300 -M6 -pA4 iPFTest cctiff -v -ir -e iPF6400_HP_ID_Satin.icm iPFTest.tif iPFTestO.tif move /Y iPFTestO.tif iPFTest.tif fakeread -v -Ir iPF6400_HP_ID_Satin.icm iPFRef Pause Print iPFTest.tif using no color management. chartread iPFTest Pause The test results will be in iPFValidate.txt colverify -v2 -N -k -s -w -x -L iPF6400_HP_ID_Satin.icm iPFRef.ti3 iPFTest.ti3 >iPFValidate.txt This seems to work OK, but chartread (like spotread, I assume, although your documentation doesn't state that either use absolute for reflective measurements) does absolute readings (probably obvious to you, but not to me). I assume, again, that the -N in colverify compensates for this ... but this is just a wild guess on my part. So, is this a correct way to validate that the print system is working correctly (profile, printer etc?). I have cctiff with -r because I'm not interested in validating an absolute colorimetric print since I never print using Abscol. Following on from that, my question was: "The reason I'm interested in going a bit further is that I would like to be able to generate a target from an image (for example a single-color gradient) in order to check out how well the profile is performing". I received no suggestions to that question (probably because there's no way of doing it using Argyll?), so I then asked a question regarding manually constructing a .ti1 file (you have XYZ values in there that seem to do nothing as far as I can see, but it took me ages to figure that out). As I was getting nowhere with this I tried spotread and got errors of around dE94 of 1.6 which seemed too high. I asked whether or not this had to do with a white point mismatch and Brad has done his best to help me, but neither of us really understands what's going on. Well, from what you say it DOES have to do with a white point mismatch since the difference between RelCol and AbsCol is effectively the white point (you will probably correct me ... but in doing so you will no doubt confuse me even more). What you don't understand, because you are so deep into all of this and know so much about it, is that having a list of commands with a bunch of parameters that do a whole lot of different things is fine for someone who really understands everything about color management, profiles ... AND ArgylCMS. For someone like me (even though I am a software engineer) half of it is gobbledygook. To get things to do what I want I have to do a lot of head-scratching, trial-and-error ... and then keep my fingers crossed that what I'm doing is right. (In fact, if it was not for DispCalGUI I would NEVER have even looked at Argyll). Of course I do have the choice of not using Argyll - after all I have purchased i1Profiler Publish ... but this seems a pity considering the months of investment I've already put into Argyll and the fact that it is undoubtedly a very flexible software suite, and that it can do some things that i1Profiler probably can't do (or at least not directly). For example, you say: "Convert the absolute target color to the device values using absolute colorimetric intent." How? In Photoshop? Using Argyll? What command? What flags? And then: "Or if you have a target color that is relative, convert to device space using relative intent, then convert that back to L*a*b* using absolute intent, and use that as your spotread verification target." How? What commands? What flags? A lot of the problems we have could be answered using a full set of usage scenarios with a clear explanation of what the commands are doing; or a fairly simple wizard-based system could guide us through the steps. A proper GUI would be wonderful, but that's a major development of course. Robert -----Original Message----- From: argyllcms-bounce@xxxxxxxxxxxxx [mailto:argyllcms-bounce@xxxxxxxxxxxxx] On Behalf Of Graeme Gill Sent: 04 November 2014 02:50 To: argyllcms@xxxxxxxxxxxxx Subject: [argyllcms] Re: Question regarding White Point and spotread robert@xxxxxxxxxxxxxxxxxx wrote: > Actually, I think the way that AbsCol is described (that is that the white > point is not shifted) is very confusing to common mortals like me. I'm not sure where you got that description from. Absolute means that the measurement is with reference to the perfect diffuse reflector. Relative means that it is with reference to the actual paper color. > I still think that it is probably necessary to compensate the spotread value > for the paper white. I think you have got it the wrong way around. Convert the absolute target color to the device values using absolute colorimetric intent. Or if you have a target color that is relative, convert to device space using relative intent, then convert that back to L*a*b* using absolute intent, and use that as your spotread verification target. (And please edit your posts. No-one wants to see the same previous emails over and over.) Graeme Gill.