"Arfa Daily"

As to purity errors being visible on black and white pictures, other than
the fact that the the phosphors have different efficiencies, and the drive
levels are different for assorted reasons, it doesn't actually matter that
much that the phosphors are being excited by the 'wrong' beams. The mix
will still make something that approximates to white - or shades of grey -
sufficiently well for it not to be glaringly obvious. More a sort of
'dirty patch' on the picture. However, as soon as a colour picture is
viewed on the same gaussed up CRT, the error is immediately visible


** I am still using a CRT monitor for my PC.

When I hold a speaker magnet about 6 inches away, white areas of the screen
become mottled with grey shadows.

However, the coloured parts change colour, blue to red, red to green etc.

QED.


..... Phil