The problem with red blindness is, one kind of sees red.

The eye has four sensor types, rgb + gray. Normal people see kind of gray + colour red. A red blind see gray and not blue and not green. This is distinct to gray or any other colour. One learns as little child - this impression is named red.
If it comes to shades of red the trouble starts. Small red in a lot of green - berries - I ignore. If somebody pointed me I can see it.
What is not working too are displays with red letters (Star gas station) against the sun light. My wife has no problem reading it, for me it is just black on black.
Red is not a signal - so red on fire-fighters car is more a kind of camouflage. Now we got those yellow strips, that helps. For a signal I would prefer yellow or orange all the time.
And a tiny small screen-number one pix width are not bright enough to do the gray +green blue trick, so to me they are black.

But for that I have a good night vision. :)

Lutz
>No idea how red/green blindness works in those grey (on grey) areas ;-)
>Setting your own colours for normal and special text would be nice
>setting browser to highly different colour schema often makes sites worse.
>I would set normal text to a much darker black - ISTR the fantastic Atari B/W monitor,
>even if it was rather small in he 80ies already..