As I was just reading a chart, bored out of my gourd and with nothing better to think about, I started randomly musing on wherever-it-is in the docs that the reason for the -e option in targen is that getting an accurate measurement of the whitepoint is important in making a good profile. And then it occurred to me that, on each and every row, the paper white gets measured twice -- at the beginning and end of each pass. (This is with my i1; not sure how other instruments work.)
Graeme, might it make sense to add an option to chartread that will remember each of those start / stop white values, average them all together, and replace every white patch in the chart with that value?
Cheers, b&