What is underpainting?
An interesting stage of painting – one often not seen or appreciated because it happens underneath the final image – is the underpainting.
Underpainting is the step after the painting surface is sealed with gesso and before starting on the final image. It’s the first layer in a painting, a base layer on top of the gesso which is not paint but a primer and one of the first decisions I need to make when I’m starting a painting. From time to time, you’ll see me use a red underpainting with acrylics, but I use other colours too (and sometimes skip this step entirely).
Why do an underpainting?
There are several benefits to underpainting, but overall, it can make a big impact on the look of a finished painting and can help me get started. As a first step in painting with acrylics, underpainting seals every pore and crevice on the canvas so if I miss a spot in the final painting the colour peeks through. It’s also an easy way to get over any mental hurdles and take any feeling of intimidation from being stared down by a blank white surface. Just ‘messing up’ a pristine canvas can be a real help some days!
One of the most important reasons to consider an underpainting is the depth and dimension it can add to the final painting. It can create levels of contrast and deepen the color intensity in the paint applied over top.
What colour to use for an underpainting?
Because the big benefit of underpainting is to deepen colour intensity, the choice of colour for an underpainting really matters. Why that is, and why I often use red can be explained with a bit of colour theory.
For impact I want to create a dynamic contrast between the underpainting and the main colours in the final painting. For a landscape this means a red underpainting. Red is complementary (opposite) to blue and green (think land and trees), and ‘hot’ compared to the ‘coolness’ of blue (think sky and water).
If I were painting an orange scene, I might choose blue for the underpainting. Again, the opposite colour to the final image: a cool/calm colour to contrast the heat/energy of orange.
You can also use a rainbow of colours underneath which results in a bright and lively piece because all of those colours peek through between the brushstrokes of the final piece.
But as with so many things, it depends. Sometimes I just start with a white underpainting because I like my whites really white and my skies to be somewhat softer than they are with an undercolour.
Every painting presents a different challenge to solve – some need to feel softer, some need to be bold – and underpainting is a great step toward the final outcome no matter what.