Wikipedia defines the underpainting partially as :In art, an underpainting is an initial layer of paint applied to a ground, which serves as a base for subsequent layers of paint.
The underpainting helps you to establish the values of your final painting. Basically it’s usually a one or maybe two colour sketch painting that you use to paint over with your final colours. Here’s an example of an underpainting with the final painting started on top of it.
This painting is no where near completion. You can see the areas of the painting that have only a brownish ( burnt umber) colour. This is the underpainting used to define the shape and the values of the painting. The values refer to the light and dark of the painting.
There is no rule saying you must have an underpainting. If , for example, you are painting a cartoon image with flat opaque colour you wouldn’t have to have an underpainting.
I mostly use a thinned, almost watery mix of paint and water ( you can add matte medium if you like if you are worried about the initial paint ‘bonding’ to you canvas or board.)
The nice thing is that whether you do an oil painting or a water based acrylic painting you can use acrylic as the basis for the underpainting. This is because oil paints will adhere or stick to water based paint…but not the other way around.
Here is another example of an underpainting in which I used two colours. This had to be adjusted because as you can see I got the direction of the light source wrong in the lower right foreground. In fact the final painting had some major changes.
So as you can see the underpainting is kind of the “unsung Hero”-the Under dog , if you will, that serves a real purpose but gets very little appreciation.
See ya next time! Happy Painting…o…and underpainting!