William Sommerwerck wrote in message
...
I have no idea if it's commonplace, but the cause is likely related to the
effect of photographs and advertisements turning magenta under exposure to
daylight.

The red filter is red because it absorbs green and blue light. Blue light
is
most-effective at breaking molecular bonds, as its photons have the
highest
energy. QED?

It might also be that the designers chose a poor-quality dye for the
filter.



Perhaps the dystuff centrifuges out to the edge ;-(
I'm surprised these colour wheels hold together as they seem to be
individual glass sectors super-glued into a disc.