gray values in a sentence

1. Sheeler had a graphic sensibility, and he did his best work in black, white and gray values.
2. This is also equivalent to using this gray value as opacity when doing  normal mode blend with black bottom layer.
3. Human perception of brightness is not linear-we do not necessarily consider that a gray value of 0.5 is halfway between black and white.
4. If one layer contains a homogeneous gray, Screen blend mode is equivalent to using this gray value as opacity when doing  normal mode blend with white top layer.
5. It's difficult to find gray values in a sentence.