What you see and how you see it is very tricky. What you photograph is also
very different from what you see.
Photos work using the 3 color model.
Your eye works by comparing the colors and shades across boundaries, so you
have color constancy across boundaries. Your brain-eye system makes the
color of objects almost constant across many lighting conditions. This is
one reason why color demos of the 3 color model are tricky. It is because
the 3 color model is not correct for human vision. And then there are women
who have 4 different cones and can be super color seers. But the 3 color
model was created by men.
Comparison is how the eye sees depth for far away objects. Motion and
comparison with other objects is used. So the Moon near the horizon looks
larger and closer than the Moon above because of comparison. I am a 3D
photographer and in 3D photos far away objects fade to a uniform flat plane.
But people with excellent visual acuity can see depth at farther distances.
A one pixel shift on an HD 1080 3D display can be readily seen as a
difference in depth. When younger I used to see fluffy cumulous clouds as
3D objects with large differences in depth. Was this an illusion? I don't
know. I could lie on the hill and watch them move over in 3D. It was
probably motion 3D and not binocular 3D, but it doesn't happen now.
So what you see in the sky is very much conditioned by other objects and can
be very subjective. Yes, the blue is created by scattering, but after that
what you see depends on your eye-brain system. Your two eyes even see
differently and sometimes you can look with one eye and see different colors
from the other one. The color constancy is very obvious to anyone who has
tried to edit 3D color photos to remove defects. One way is to clone things
from the good frame to the defective frame. But when you do that often the
colors that look the same in each frame do not match. Getting thigs right
is very tricky in 3D editing.
Look at a patch of the sky through a canopy of leaves, and then find an open
spot to view the same patch of sky. The colors are different!