Originally Posted by buzzard767
The Accupel is putting out some incorrect signals in the Color module. These with 8 bit RGB.
OK, I am able to confirm one bug. At 75% intensity, the 75% of Rec. 709 white is at PC level (764), but the ACM white is at video level (720). Video is correct. 100% intensity, both are at video level (940). That would explain the difference in relative luminance of red you see between the two modules. However, the bigger problem you see, which is lower saturation in ACM than in 75% of Rec. 709 (which would not be affected by the white level discrepancy) I still do not see, either at 100% or 75% intensity.
ACM 100% intensity, 75% saturation
Color Management 100% intensity 75% of Rec. 709
ACM 75% intensity, 75% saturation
Color Management 75% intensity 75% of Rec. 709
BTW, bugs like this are not AccuPel issues, they are CP programming errors. We are just sending the wrong USB command for white in Color Management 75% intensity 75% of Rec. 709.
One further point: When testing this I am not merely taking measurements off the screen. I am also monitoring the signals sent from CP to the AccuPel using third-party software. There is nothing in the USB traffic to explain the loss in saturation you seem to be measuring in ACM, so I am at a loss to explain this.Edited by TomHuffman - 4/23/13 at 11:50pm