Hi, With these commands: targen -v -d4 -p1.88 -s200 -e4 -f0 Printer_calibration printtarg -v -ii1 -R123 -pA4 Printer_calibration in version 1.6.2 printtarg output: .... After optimisation, worst delta E = 66.372105 Worst case direction distinction delta E = 61.873128 In version 1.6.3 i have (the same commands): .... After optimisation, worst delta E = 21.000236 Worst case direction distinction delta E = 21.914342 Is such a difference normal? Michał