Menu Colour

[sambat]

I create a still menu screen which has a white background and saved as a .bmp file.
Using MuxMan I create the video still - but the white background is now grey.
Note that the grey is only seen when playing back with a media player - if a snapshot is taken, the captured image reverts to white.
Also If the project is burned to DVD, it is still white when played back on the TV.
I've touched up the grey to emphasize the effect - it's lighter than that on playback.
Is this a setting on by display that needs tweaked?
I dragged the VIDEO_TS.VOB file into VirtualDub and it shows the input pane grey and the output white.