Why are contrast and chiaroscuro an important part of realistic painting?

It adds volume to the painting and makes it look 3D, without it the painting would look flat and cartoony.

1. red- the color of blood

2. black- the color of the darkness in my soul

3. white- the color of the clouds

4. orange- a fruit

5. blue- the color of water

the amount of fabric used and the collar fitting and sleeve lenghts are the two options, that to me, make the most sense.

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