All 3 Uses of

contrast
in
The Memory Keeper’s Daughter

...a series of photos of a human vein, taken in sequence, in gradations of precisely controlled light, the level of contrast changing subtly with each one.
p. 152.7 *

contrast = difference between tones of an image

Doro's hair was pure white now, in striking contrast to her dark eyes, her smooth olive skin.
p. 159.8 *

contrast = notable difference

Norah thought of Sam's bedroom, the riot of colors there, and how tranquil this seemed in contrast, the colors stable, fixed, falling through the air.
p. 304.2 *

in contrast = a comparison that shows differences

Definitions:

(1) (contrast as in: contrast their writing styles)
point to differences between; or compare to show differences
(2) (contrast as in: there is a contrast)
a difference -- especially a notable difference; or the side-x-side arrangement of things that draws attention to an unmissable difference
(3) (contrast as in: sharpen the picture contrast)
the difference between tones of an image -- as in a photo or video -- such as the quality of brightness or the intensity of shades or colors