There are three QTR profiling scripts to choose from:
QTR-CREATE-ICC
QTR-CREATE-ICC-RGB
QTR-LINEARIZE-DATA
I don't remember which one I ran. Is there a difference between these?
In QTR you start with the linearize tool after the partitioning of the inks and use that in the QTR driver. Then you can build the ICC profile and depending on the application you print from you can select the top one for greyscale or the RGB one if the application is not reliable with a greyscale ICC profile.
If it is about ICC profiling an ABW mode of an OEM driver, Epson, HP, etc, you use the RGB one and you have to rely on ABW being linear already or the linear character is made in the calibration step of the printer (HP). The last is what I use with my HP Z3100. Qimage to print from.
There is another possibility with the normal drivers where you create curves in Photoshop to linearize the print more by trial and error (OEM inks) or partition/linearize custom quad inks and incorporate the curves in an ICC printer profile with the ICC profile creator. Use the RGB one is my advice. Paul Roark asked Roy to implant that feature. That is what I use to drive an HP Officejet K5400 with 4 diluted HP Vivera monochrome inks. Qimage to print from.
You can still shift things that they become more to your taste if for example the viewing light is too low to show the density steps in the shadows. The (spectro)meter measured density differences so the paper can cope and a bad meter would probably have difficulty to distinguish differences in the shadows instead of exaggerate them.
Some time after the QTR tools were created for QTR itself QTR (linearisation and) profiling for OEM drivers started with the appearance of ABW in the Epson 2400 (Steve Kale) and not before ABW appeared. It is more likely that ABW got better in time.
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Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htmJuly 2013, 500+ inkjet media white spectral plots.