Not able to read well on Pixel xl

[Android Central Question]

Previously, I was using Samsung A7 (2015). Now, I bought Pixel 1 XL. Since I use the phone mostly for reading, I find A7 (2015) very good for reading whereas I get eye pain and eye strain on reading on Pixel 1 XL. I felt it may be because samsung A7 (2015) had white colour screen while Pixel 1 XL had slightly blue colour screen. So, I tried an app called Reading Mode and adjusted background colour. Even after adjusting colour I found by comparing both phones that, the A7 (2015) had high contrast. Background was exactly white and black letters were very darkly bright. While Pixel 1 XL had letters in grey colour. How can I change Pixel 1 XL's background so that its white in background and characters/letters very dark? Or if the problem is something else, Kindly tell what I should do..?