Here are my pictures of my Paperwhite. I got it on October 2d. The first picture is how I usually have the light (at 15) while the second is at full brightness - which I find to be too bright. The picture was taken in my home office with no artificial light on (there's a window to the left - it's a cloudy day at 3:30 pm EST). I took the picture on my iPhone 4S with no flash.
Sometimes, I can see some green or pink. But, I really don't notice any discoloration while reading.