10 Things About Painting Shadows
Updated: Mar 15, 2021
The Shadow Knows...

"No shadow is black. It always has a colour. Nature knows only colours … white and black are not colours."
There are two types of shadows. FORM shadows and CAST shadows.
Form shadows are the shadows that are on an actual physical object, like the shadow side of a tree. Cast shadows are the shadows that the tree itself casts upon another object, like the shadow that the tree casts upon the ground.
Let's dive a little deeper...
The stronger the light source the darker the cast shadow.
Strong Light = Dark Shadow
Weak Light = Light Shadow
The higher the light source to the object the shorter the shadow. e.g. Midday shadow vs afternoon shadow.
Form shadows have soft edges and cast shadows have harder edges.
The light side of and object is lit by sunlight which is generally a warm light. The shadow side is lit by sky light which is cooler in temperature than the sunlight. (sneak in a little violet)
The colour of the shadow is comprised of three elements. a.) A large amount of local colour (the actual colour of the the object) . b.) The complimentary colour of the light source. c.) A small amount of a dark accent. It's this dark accent that will set the shadow off. If your shadow is too dark, the accent won't make enough of a difference to make the shadow luminous.

In this John Poon painting notice the small amounts of dark accents that ground the tree and bring the shadows to life
Generally, cast shadows are cool and form shadows are warmer than cast shadows.
To get a feeling of light, you really need to paint the shadows correctly.
Black in light can be lighter in tone than white in shadow. Mind melt… SEE THIS ARTICLE
Try to connect your cast shadow and form shadow by painting them at the same time with a soft edge between
Take note of reflected light but suggest it rather than going overboard with it. Make it subtle.
(bonus) Render your lights and simplify your shadows (no detail)
NOTE: Shadows should be painted translucent. But this works only if you get the colour right. If you don't, it won't matter whether you paint them translucent or opaque, they won't look right and your work will suffer. Paint them the right value and temperature, and it won't matter if they're opaque or translucent - they will look right.
Thanks for coming out to paint with me,
Doug.