Tilo Nitzsche wrote:
Under Windows XP, dispread can profile the laptop display fine. However when trying to calibrate a Dell 1905FP (19" TFT, Samsung PVA panel), it hangs for maybe 30s when trying to read dark patches and then times out. (dispread -v -yl -K -p 0.5,0.5,2.0 dell1905)
Was this also under XP, or was it Linux ? It's hard to explain this problem. The closest I can get is that indeed there is an issue with instrument commencing measurement before the new patch is stable on the display. There are two phases to each Display 2 LCD read operation, the first being a preliminary reading to establish a scale factor, followed by the real reading using that scale factor. The scale factor and the light level sets the time it takes for the second reading to complete. So if there was a preceding bright patch that was still being displayed as the preliminary reading was being done, there would be a high scale factor (integration target threshold ?) set, and then if during the second phase the displayed level drops to black, the instrument won't respond for some time (minutes ?), because the integration will take a long time to reach the high threshold. The preliminary reading takes about 120 msec from start to finish, so if this is the explanation, it's hard to guess how much delay there is from setting a patch color to it actually turning up on the display. > My impression was that i1 Match and basICColor Display don't display dark > patches longer than others (using the same Eye-One Display 2). So perhaps > there is some reading mode that uses a fixed measurement time. They usually take between 0.5 and 7 seconds. I think there is a bug in the Gretag driver that sometimes causes even longer measurement times than this too. I'll see about uploading a version of the code (V0.70 Beta 4) that adds a 50msec delay before doing a display reading, so that you can see if this makes any difference to the problem. Graeme Gill.