Hi I go on with my investigations... If I download the x86 binary on the site, it seems to work in 32bit. It must be a 64bit issue, if someone has an idea of this issue and want me to test, no problem. Yet, it does not totally work, dispcal fails to create the calibration file. I detect two strange things: the target black got a nan value and it fails with a conjgrad error: :~/test32/bin$ ./dispcal -i92 -a ../log/test Offset calibration: Place instrument on a dark surface. Hit Esc to skip, any other key to start calibration: Offset calibration successful The instrument can be removed from the dark surface. Cell ratio calibration: Place instrument on test window. Hit Esc to skip, any other key to start calibration: Cell ratio calibration successful The instrument can be removed from the screen. Place instrument on test window. Hit Esc to give up, any other key to continue: Press 1 .. 7 1) Black level (CRT: Brightness) 2) White point (Color temperature, R,G,B, Gain) 3) White level (CRT: Contrast, LCD: Brightness) 4) Black point (R,G,B, Offset) 5) Check all 6) Continue on to calibration 7) Exit Doing some initial measurements Adjust CRT brightness to get target level. Press space when done. Target 0.45 \ Current 0.00 + Press 1 .. 7 1) Black level (CRT: Brightness) 2) White point (Color temperature, R,G,B, Gain) 3) White level (CRT: Contrast, LCD: Brightness) 4) Black point (R,G,B, Offset) 5) Check all 6) Continue on to calibration 7) Exit Doing check measurements Current Brightness = 44.65 Target 50% Level = 9.72, Current = 6.68, error = -6.8% Target Near Black = 0.45, Current = 0.00, error = -1.0% Current white = x 0.3015, y 0.3077, VDT 7958K DE 6.6 Target black = x 0.3015, y 0.3077, Current = x 0.0000, y 0.0000, error = nan DE Press 1 .. 7 1) Black level (CRT: Brightness) 2) White point (Color temperature, R,G,B, Gain) 3) White level (CRT: Contrast, LCD: Brightness) 4) Black point (R,G,B, Offset) 5) Check all 6) Continue on to calibration 7) Exit dispcal: Error - Conjgrad failed Any help appreciated ;-) Mike