Today, I began to add color over the underpainting of a woman.
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The left photo shows the purplish brown glaze(thin transparent paint) applied over the red and white underpainting. The photo on the right shows the portrait 90% completed, opaque oil paint applied in the areas the the light has touched the face. I leave the glaze paint in the shadows untouched.
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This technique causes the light to appear more illuminating.
Once this layer is dry I will apply a few glazes in select places to either darken or enrich the skin color more.