Underpainting: A Quiet Start for Stronger Oils

An underpainting is a first layer that settles the drawing and the tones before full colour arrives. It might be a grey grisaille, a warm earth veil, or a wipe-out in which you tone the surface and lift the lights with a rag. The aim is not a finished picture in disguise. The aim is to give later paint something true to sit on, so colour is a decision rather than a rescue.

Grey, warm or wiped away

A grisaille uses a narrow range of greys so you can see whether the design holds without the distraction of hue. Mix those greys from a small group of colours rather than from black alone, or they turn sour and dead. Mixing Natural Greys is the practical companion. A warm ground, often a thin earth, does a different job. It can glow through later strokes and stop shadows going chilly by accident. How temperature builds depth is discussed in Warm and Cool Colours. Use that idea once in the ground, then stop arguing with it.

Wipe-out is the fastest of the three. Rub a thin mid-tone over the panel, then lift the lights with a rag or a dry brush. In a short time you can see the light of the room sitting on the object. It is a sound start for a study you will finish today, and a patient start for a picture you mean to glaze.

Keep the first layer lean

The underpainting should be thin. Paint with little or no extra oil grips the ground and gives later, slightly richer layers a fair chance to follow. A greasy first coat is a poor foundation. You will fight it, or you will paint into a film that stays soft. If you intend to glaze, wait until this layer is dry to the touch and no longer cool or tacky. Glazing into a half-dry start lifts both layers and muddies them. The glazing method itself is set out in Glazing for Luminous Colour.

Drying depends on the pigment, the thickness and the room. Many earth colours set sooner than a heavy black. Do not trust a timetable you cannot feel. Touch a spare edge of the study, not the best passage, and believe your finger more than the clock.

What to solve now

Solve the large masses of value, the placement of the subject, and two or three edges that carry the drawing. Leave small details out. A lace of tiny marks becomes a nuisance once colour covers it. You either lose it or trace it with anxiety. Think of the underpainting as a map of weight: where the picture is heavy, where it is light, and where an edge must stay found.

This is also the cheap moment to notice a weak composition. If the cup is a pea in a field of empty panel, change it now. Scraping a thin veil is easy. Scraping a week of colour is not. Squint at the study. If you cannot tell what the light is doing, the next hue will not explain it for you.

A sequence you can repeat

Tone the surface with grey or warm earth, thin enough that the ground still shows in places. Establish the darkest darks and the main light shapes. Soften only the turns that are truly soft. Step back until the study reads across the room with colour ignored. If it reads, let it dry. If it does not, adjust the masses before you congratulate yourself on the tint of the ground.

When you return, keep the first full-colour pass respectful. You do not need to cover every inch on principle. A little of the ground breathing at an edge is often more alive than a sealed skin of paint. Match the care of the start, rather than burying it.

Frequently asked questions

Do I have to use grey? No. Grey makes value easy to judge. A warm earth can make later colour feel lit from underneath. Choose the problem you actually have, not the method you saw last.

Can I underpaint in acrylic and finish in oil? Many painters do, because a thin acrylic layer dries quickly and stays lean. Let it dry fully, and keep the oil layers slightly richer than that base. If a product label disagrees with studio folklore, follow the label.

What if the underpainting looks better than the colour? That usually means the colour layer has become fussier than the start. Simplify the next pass until it is as clear as the grisaille was. You can always add a detail later. You cannot easily unclutter a surface you have worried to death.