Quick answer: The best oil underpainting tips come down to three rules: keep the underpainting thin and lean (paint thinned with solvent, little or no added oil), work in a single color or a limited earth palette to settle values first, and let it dry to the touch before painting over it. Burnt umber, raw umber or a transparent red oxide thinned with odorless mineral spirits dries fast and gives a solid foundation for later layers.
An underpainting is the first layer of an oil painting, laid down to fix composition, drawing and light-and-dark structure before color arrives. These oil underpainting tips cover which colors to use, how thin to go, how long to wait, and the mistakes that cause cracking or muddy color later. Done well, an underpainting makes the rest of the painting faster and more confident.
Anyone working from a starter set already has what they need: most oil painting kits made for beginners include burnt umber or burnt sienna, which are two of the most practical underpainting colors.
What an Oil Underpainting Does
Oil paint can be built up in many layers, so the first layer can carry different jobs from the last. An underpainting:
- Solves the drawing. Placement and proportion get corrected while the paint is still thin and easy to wipe.
- Establishes values. The pattern of lights, midtones and darks is decided before color complicates it.
- Kills the white canvas. A stark white ground makes it hard to judge values; a toned layer gives a middle reference.
- Adds color depth. Warm underlayers peeking through cool top layers (or the reverse) create vibration that flat color cannot.
Types of Oil Underpainting
| Type | Colors | What it is good for |
|---|---|---|
| Brunaille | Browns such as burnt umber or raw umber | Fast drying, general-purpose value studies, landscapes and portraits |
| Grisaille | Grays mixed from black and white or ultramarine and umber | Precise value control, later glazing with transparent color |
| Verdaccio | Greenish gray (often black, white and yellow ochre) | Portraits, where green underneath neutralizes pinkish flesh tones |
| Imprimatura | One transparent wash over the whole canvas | Toning the ground before drawing; not a full value study |
| Colored block-in | Simplified local colors, thinly applied | Alla prima approaches where the underpainting is partly kept |
For a first attempt, a brunaille in burnt umber is the most forgiving. It dries quickly because umber contains manganese, which speeds oxidation, and it gives a warm base that suits most subjects.
Materials for an Oil Underpainting
- A primed canvas or panel (acrylic gesso or oil ground)
- Burnt umber, raw umber, burnt sienna or transparent red oxide
- Odorless mineral spirits or another artist-grade solvent
- Medium-sized filbert or flat bristle brushes, plus a small round for drawing
- Lint-free rags or paper towels for wiping out lights
- Optional: a fast-drying alkyd medium if you want the layer dry overnight
Oil Underpainting Tips, Step by Step
- Tone the surface (optional). Rub a thin wash of burnt sienna or umber thinned with solvent over the whole canvas, then wipe with a rag until it is a mid-light value. Let it set for 10 to 20 minutes.
- Draw with thinned paint. Mix umber with solvent to a watery ink consistency. Sketch major shapes using a small round. Keep lines light so they can be corrected.
- Block in the darks. Use a bigger brush and slightly less solvent. Fill the darkest shapes as single masses rather than many small details.
- Develop midtones. Thin the paint more for lighter halftones, or scrub a thin layer and partially wipe it.
- Lift out the lights. Wipe highlights with a clean rag or a brush dampened in solvent. This subtractive method is fast and keeps the layer thin.
- Squint and check. Squint at the painting and the reference. If the value pattern reads correctly in a blur, the underpainting is doing its job.
- Stop early. Resist fine detail. The underpainting is structure, not a finished monochrome.
- Let it dry. A thin umber layer thinned with solvent is often touch-dry in several hours to a day, depending on temperature, humidity and thickness.
Fat Over Lean: The Rule That Keeps Paintings From Cracking
Oil paint dries by oxidation, not evaporation, and layers with more oil stay flexible longer. If a lean (low-oil) layer sits on top of a fat (oily) layer, the top layer can crack as the lower one keeps moving. That is why the underpainting must be the leanest layer in the painting.
Practical ways to keep the underpainting lean:
- Thin paint with solvent rather than oil.
- Do not add linseed oil or slow-drying mediums at this stage.
- Keep the layer thin enough that canvas texture still shows.
- Add a little more oil (or medium) in each later layer.
A practical progression: underpainting with solvent only; middle layers with a small amount of medium; final layers with slightly more medium or straight from the tube.
Best Colors for Oil Underpainting
Burnt umber
Fast drying, warm, and dark enough for strong shadows. It is the default brunaille color for many painters.
Raw umber
Cooler and greener than burnt umber, also quick-drying. Good under cool landscapes and for a more neutral value study.
Burnt sienna and transparent red oxide
Warm, glowing and transparent when thin. Excellent as an imprimatura or under skies and skin, where warm spots peeking through cool color add life.
Ultramarine and burnt umber mix
This pair makes a near-black that can be warmed or cooled. Useful when you want a neutral grisaille feel without using black paint.
Avoid slow-drying colors for underpaintings unless you plan to wait. Some cadmiums, alizarin crimson and ivory black can take noticeably longer to dry, and titanium white in thick passages also slows things down.
How Long to Let an Oil Underpainting Dry
“Dry” for an underpainting usually means dry to the touch: a light touch leaves no paint on your finger and the surface does not feel tacky. Typical guidance:
- Thin umber or sienna with solvent: often a few hours to overnight.
- With an alkyd medium: often overnight.
- Thicker passages or slow pigments: two to several days.
Some painters work wet-into-wet over a still-tacky underpainting, which blends the layers and suits alla prima. That is fine as long as you accept that the colors will mix with the brown below.
Oil Underpainting Tips for Beginners
- Use one color only for your first few paintings. It forces attention onto values.
- Limit yourself to three or four values: light, light-middle, dark-middle and dark.
- Use a bigger brush than feels comfortable. It prevents premature detail.
- Take a photo of the underpainting in grayscale on your phone to check values.
- Paint small, such as 8×10 or 9×12 inches, so you can practice the process repeatedly.
Advanced Tips for Underpainting in Oils
- Use complementary undertones. A warm red-orange underpainting beneath green foliage or blue sky makes the top color look more vivid where it breaks through.
- Plan for glazing. If you will glaze transparent colors later, make the underpainting slightly lighter than the final value, since glazes darken.
- Use opaque white sparingly. A grisaille may include white, but keep it thin to avoid slow-drying, fat passages under lean ones.
- Leave some underpainting visible. Strategic gaps in later layers give unity, especially in loose landscapes.
Common Oil Underpainting Mistakes
| Mistake | What happens | Fix |
|---|---|---|
| Using oil or medium in the first layer | Later layers can crack or wrinkle; slow drying | Thin with solvent only at this stage |
| Applying it too thick | Long drying times; texture fights later brushwork | Scrub thin; canvas weave should still show |
| Too much detail | Time wasted; you paint over it anyway | Stop at big shapes and values |
| Values too dark everywhere | Painting turns heavy and muddy | Wipe out lights generously; keep shadows simple |
| Painting over a wet, slick underlayer by accident | Colors turn muddy | Wait until touch-dry, or embrace wet-in-wet deliberately |
Do You Always Need an Underpainting?
No. Many alla prima painters go straight to color on a toned canvas. An underpainting is most helpful for complex compositions, portraits, layered glazing and anyone still developing drawing confidence. For quick plein air studies, a toned ground and loose block-in may be enough.
Preparing the Surface Before You Underpaint
The underpainting behaves very differently depending on what it sits on. A surface that is too absorbent drinks the thin paint and leaves a dry, patchy stain; a surface that is too slick lets the paint bead and slide. Getting the ground right is one of the most overlooked oil underpainting tips.
- Pre-primed cotton canvas. Most store-bought canvases are coated with acrylic gesso. They work well, though some are quite absorbent. A single extra coat of gesso, lightly sanded once dry, gives a smoother and more even surface.
- Gessoed panels. Hardboard or wood panels primed with several thin coats of gesso give a smooth, rigid surface that suits detailed underpaintings and wipe-out techniques.
- Oil-primed linen. Less absorbent and slicker. Thin paint moves around more, so use a slightly drier brush and give the layer a little longer before wiping.
- Canvas paper and boards. Fine for practice studies. They are more absorbent, so the underpainting dries quickly but can look streaky.
A quick test: brush a little thinned umber in a corner. If it disappears into the surface within seconds, the ground is very absorbent and an extra coat of primer will help. If it beads up, lightly sand the surface or rub it with a rag dampened in solvent before starting.
The Wipe-Out Method in Detail
The wipe-out (or rub-out) method is the most efficient way to make a brunaille, and it is ideal for anyone who finds drawing with a brush intimidating. You work subtractively, like charcoal on toned paper.
- Cover the entire canvas with a thin, even layer of burnt umber thinned with a little solvent. It should look like a mid-dark brown stain.
- Wait 5 to 15 minutes so the solvent evaporates slightly and the paint becomes a little tacky. Too wet and it smears; too dry and it will not lift.
- Wrap a lint-free rag around one finger and wipe away the largest light shapes first.
- Use a clean flat brush dampened (not dripping) with solvent to lift smaller lights and sharpen edges.
- Use a cotton swab or the corner of a rubber color shaper for the brightest small highlights.
- Add darker accents with a brush and slightly thicker umber where the shadows need more weight.
The method keeps the underpainting thin by nature, which helps with fat over lean, and it encourages thinking in large light and dark masses rather than outlines.
Underpainting Approaches by Subject
Landscapes
A warm burnt sienna or red oxide underpainting under skies and greenery is a classic choice. Small gaps of warm color between strokes of blue and green add energy. Keep the sky area light in value so the final sky stays luminous.
Portraits
A verdaccio or a raw umber underpainting helps judge the subtle value shifts in a face. Concentrate on the big planes: the shadow side of the face, the eye sockets, the underside of the nose and the cast shadow under the chin. Features can be refined later in color.
Still life
A grisaille or brunaille works well for objects with strong light from one direction. Pay attention to cast shadows and reflected light, since they give the objects weight. Lay out the background value early; it changes how every object reads.
Seascapes and night scenes
A cool underpainting in ultramarine and umber can set the mood for darker scenes. For sunsets, a warm orange imprimatura lets golden light show through later cool layers.
Moving From Underpainting to Color
Once the underpainting is dry to the touch, the next layer is often called the dead layer or first color layer. A few practical points:
- Begin with the darks and midtones in thin color, matching the underpainting’s values.
- Add a very small amount of medium to the paint now, so this layer is slightly fatter than the one below.
- Let some underpainting show in transitions or shadows where its warmth helps.
- Build lights last and thickest; opaque light passages over a thin dark base read as more solid.
If the underpainting looks too dark after drying, you can scumble a thin, semi-opaque light layer over parts of it, or simply paint more opaquely in the next layer. Don’t try to rework the underpainting itself once it has set; that tends to create a muddy, thicker layer that breaks the lean-first principle.
Safety and Cleanup
Use odorless mineral spirits or another artist-grade solvent in a ventilated room, keep containers closed, and dispose of solvent-soaked rags safely. Rags with oil on them can heat up as they oxidize, so lay them flat to dry outdoors or store them in a sealed metal container with water before disposal, following local rules.
FAQs
What color is best for an oil underpainting?
Burnt umber is the most common choice because it dries fast and covers a full value range. Raw umber and burnt sienna are popular alternatives.
Can I use acrylic paint for an oil underpainting?
Yes. Acrylic dries in minutes and oil adheres well to it. Keep it thin and matte, and never put acrylic over oil.
Should an underpainting be lighter or darker than the final painting?
Generally slightly lighter in the lights and similar in the darks, especially if glazes will follow, because transparent layers darken values.
How thin should an oil underpainting be?
Thin enough that the canvas texture shows through. It should feel like a stain rather than a layer of paint.
Can I paint over a wet underpainting?
You can, but the colors will blend with it. For clean color, wait until it is dry to the touch.
Do I need to varnish or seal the underpainting?
No. Paint directly over a dry underpainting. Varnish is only applied to the finished painting once it is fully cured.
Next Step
Underpainting is one of the fastest ways to make oil painting feel controlled instead of chaotic. Start with a single earth color, keep it lean, and let it dry before adding color. If you still need a well-rounded set of tubes, brushes and solvent to practice these steps, see our roundup of starter oil painting sets worth considering.
