Now you can have a look at some pictures and watch how the
computer quantises the colours. Click HERE to see a fractal image
(23K bytes). This image contains 72 colours. Now click the right
mouse button in the picture to bring up XV's control panel. You
will see a message saying how many colours XV 'got'. As this
image contains relatively few colours, it may say something like:
'Got all 72 desired colours.'
'Got 150 out of 200 (150 unique)'.
You may like to try putting a colourful gif up as a background to your window manager and seeing if this affects how many colours XV can 'get'.