If a person is red color blind, what do they see instead of the color red?

Question

do they see it in grayscale/black and white, or do they not see it at all. For example, if a person is looking at something that has a white background and red text, do they see all white, or does the red text show in black and white?

Answer 1

They see different shades of grey.

Answer 2

usually when some1 is colorblind to red it called red-green color blindness. they cant tell the difference between red and green color blindness, its very common and about 1/5 males have some form of it

http://en.wikipedia.org/wiki/Color_blind...

the second line of colors is wut it looks like

Answer 3

Red appears as black, although most colour blind people (including complete achromats) can differentiate black and red in some lighting situations.

Answer 4

I think they see like grey instead.

I'm not sure though.