Sometimes 20/20 vision is not helpful. When we observe whatever we are drawing there is a ton of information going in through the eye gate. And an image filled with needless details cripples the effect of a piece. The goal is to edit and simplify.
Squinting our eyes just enough simplifies values and over all helps us to see a simplified version of what we are looking at. Squinting also helps you to see simple shapes very clearly. Nailing those simple shapes helps with the overall essence of the piece.
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