Easy Light Direction Reminder
by Robert Sloan
(Russellville, Arkansas, USA)
Get a pack of sticky notes. Draw an arrow on one with a Sharpie or other big marker. Stick it to the corner of the paper just outside your painting, or just outside the border of the painting with the arrow pointing in the direction of the light.
With sticky notes, you can reuse the same one for several paintings until the sticky wears off. Keeping it handy stuck to your table or easel will remind you to check and mark light direction anyway.
Just don't let your spouse move it not realizing what it is, or you could have bi-directional light...