Here’s a brief but important post for Color Sunday. If you prime your panels with a tint of venetian red or burnt sienna, you can get a good base for many kinds of paintings.
A warm underpainting is especially helpful for paintings of skies or foliage, or any painting with a blue or green tonality. The little bits of color that inevitably remain between your strokes will make blues or greens sparkle by complementary contrast.
An insistent warm underpainting also can act to force you to cover the background with opaques. This 6 by 4 inch painting of an elephant from the zoo is just partially finished. Normally I would cover the entire red-orange surface with opaque paint.
For plein air painting I use Gamblin oil priming, which I buy in a quart tin, and tint it using using a palette knife on a scrap of palette paper. A drop or two of cobalt drier will get the priming to set up overnight if you’re prepping for a painting trip.
For studio work I will more often prime with gesso tinted with acrylic, as this surface allows for a pencil preliminary drawing.