Thank you Michael.

So I did some experiments.
When I take off my glasses, the effect goes away.
When I look through the reader portion of the glasses, the effect tends to go away.
And maybe there is some of that mach banding going on, for that white effect.
So I'll blame most of the effect on the age of this user :-)
And I'll keep using the dark red for y-axis, rather than red.

- Brian