What is Underpainting in Acrylic Painting? A Complete Guide

Most acrylic paintings that look flat have the same problem: no tonal foundation underneath the color.

Understanding underpainting in acrylic painting is what separates a muddy, overworked canvas from one with real depth, contrast, and form. It is a technique rooted in Renaissance practice, used by painters from Leonardo da Vinci to modern realists, and it transfers directly to acrylic work.

This article covers what underpainting is, why it works, which techniques to use, and when to skip it entirely.

By the end, you will know how to build a solid value structure before color ever touches the canvas.

What is Underpainting in Acrylic Painting

Underpainting is a preliminary paint layer applied directly to the canvas before any final color goes down. It maps out the tonal structure, light sources, and compositional balance of the piece, so that every subsequent layer has something to build on.

In acrylic painting, underpainting works particularly well because acrylics dry fast. You can lay down a full value map, wait 20 minutes, and start glazing. Compare that to oil underpainting, which can take days to cure before you can safely paint over it.

It is not a sketch. It is not a base coat. A sketch gives you line information. A base coat gives you a surface color. Underpainting gives you tonal depth, which is something neither of those other steps can do on their own.

Understanding underpainting also means understanding value in painting — the scale of light to dark that gives a flat canvas the appearance of three-dimensional form. Without a solid value structure under your colors, even technically correct color mixing can look flat.

According to Industry Research data from 2023-2024, water-based acrylics now hold a 32% share of product volumes globally, driven in part by their suitability for layered techniques exactly like underpainting. The technique itself is centuries old, but its use in acrylic work has become standard practice for portrait, landscape, and still life painters alike.

The Purpose of Underpainting

The main job of an underpainting is to separate two of the hardest problems in painting: value and color. Trying to get both right at the same time is genuinely tricky, and most beginners run into muddy, flat results when they attempt it without a foundation layer first.

Value first, color second is not just a preference. It is a logical workflow. Once your lights and darks are locked in underneath, you are free to focus on temperature, saturation, and hue during the final layers without second-guessing the structure.

Other key reasons painters use underpainting:

• Eliminates the intimidation of a stark white canvas
• Reduces overpainting and wasted layers in the final stages
• Gives transparent and semi-transparent colors something to interact with visually
• Pre-defines areas of shadow so dark paint does not have to work as hard later
• Helps maintain color harmony across the full composition

There is a practical efficiency argument too. Riley Street Art Supply’s research into layered acrylic workflows notes that a solid tonal underpainting significantly reduces the number of corrective layers needed later. Less rework, cleaner paint surface, better final result.

Painters working in portrait painting benefit especially. Skin tones are notoriously difficult to mix at the right value. Starting with a monochromatic wash that maps the light and shadow of the face means that when you apply flesh color, you are only solving one problem at a time.

Key takeaway: underpainting is not about adding steps. It is about removing complexity from later stages so that the work flows with more control and less correction.

Underpainting Techniques for Acrylics

There are four main approaches, and they serve genuinely different purposes. Picking the wrong one for a given subject can work against you, so it is worth knowing what each one does before choosing.

Grisaille

Gray-scale underpainting — built from black and white, sometimes with a touch of raw umber to warm the neutral. Grisaille has been used since the early Renaissance. Painters including Rembrandt van Rijn and Peter Paul Rubens used it as the structural foundation for their most complex compositions.

It creates a complete value map before any color decisions are made. In acrylic work, grisaille dries in minutes, making it fast to build. The challenge is that pure black-and-white grays can slightly desaturate final colors if the underpainting shows through, so many artists add a small amount of burnt umber or blue to shift the temperature.

Works particularly well under glazing in acrylic painting, since transparent color over a grisaille creates optically mixed tones that look richer than mixed paint alone.

Monochromatic Underpainting

Instead of gray, you use a single earth-tone pigment diluted to varying transparency levels. Burnt sienna, raw umber, and Payne’s gray are the most common choices.

Why earth tones work: they are warm, transparent, and easy to overpaint without creating visual noise. Raw umber in particular dries to a neutral tone that sits quietly under almost any color without distorting it.

This is the most forgiving approach for beginners. The single-color constraint forces a clear focus on shape and value, which trains the eye faster than jumping straight into full color work. Most painters working in landscape painting default to this method for its speed and flexibility.

Imprimatura

A thin, transparent wash of color across the entire canvas surface. It does not model the form in detail. Instead, it kills the white ground and sets a color temperature that will influence every layer above it.

A warm imprimatura (burnt sienna, yellow ochre) pushes the whole painting toward warmth. A cool one (blue-gray, Payne’s gray) sets a cooler, more atmospheric mood. This bleed-through effect is subtle but real. You can feel it in the final piece even when the imprimatura is barely visible.

Technically, it is closer to a toned ground than a full underpainting. But for loose, gestural, or abstract work, it is often all the foundation a painter needs before blocking in color directly.

Colors Commonly Used for Underpainting

The underpainting color is not neutral. It actively participates in the final result, so choosing it without thinking about your top layers is a mistake that shows up later.

Most-used underpainting pigments:

• Raw umber: cool, neutral, transparent — sits under almost any color without interference
• Burnt sienna: warm, mid-dark value — good for portraits and warm-toned subjects
• Payne’s gray: cool, slightly blue-black — works well for dramatic, high-contrast work and landscapes
• Yellow ochre + black + white (verdaccio mix): the traditional greenish-gray for skin tones

Complementary color underpaintings are a more advanced choice. Using a red-orange underpainting beneath a foliage-heavy landscape, for example, creates visual tension where the color bleeds through gaps in the green. Color theory explains this: complementary pairs intensify each other at the edges. The result is a painting with more apparent vibrancy than one painted on a neutral ground.

According to the verdaccio tradition documented in Cennino Cennini’s Il Libro dell’Arte, the greenish tone works because it is the complement of the reddish pigments used in flesh. Light travels through the upper paint layers, interacts with the green underneath, and returns a warmer, more luminous tone than flat mixed flesh color ever could.

One practical note: avoid bright or heavily saturated underpainting colors unless you know exactly what you want. Vivid underpainting bleeds through even opaque top layers in ways that are hard to predict and harder to fix. Neutrals and earth tones are slower to cause problems.

How to Do an Underpainting with Acrylics

The process itself is not complicated, but a few specific choices affect whether the underpainting actually helps or just adds a step.

Step-by-step acrylic underpainting process:

1. Prepare the surface. Canvas should be primed with gesso. If you are unsure about how to prime a canvas, apply two coats and let each dry fully before continuing.
2. Transfer your composition lightly in pencil or charcoal. The underpainting will cover most of it, so keep marks light.
3. Dilute your chosen color with water to a wash consistency. It should flow easily from the brush and be slightly transparent.
4. Block in the darkest values first. Use the diluted wash to establish shadows, dark masses, and the deepest areas of the composition.
5. Build mid-tones next, using slightly less dilution. Let the white canvas or toned ground show through in areas that will be the lightest.
6. Let it dry completely. Acrylics dry quickly, but make sure the surface is not tacky before adding color layers.

Common mistakes to avoid:

• Going too thick or opaque — a heavy underpainting is hard to paint over and loses its purpose
• Skipping the drying step — wet underpainting mixes physically with top layers and muddies the color
• Ignoring value contrast — a flat, low-contrast underpainting gives you nothing useful to build on

Jackson’s Art Blog notes that the definition of an underpainting is flexible. It can be as minimal as a toned ground with a few gestural marks, or as detailed as a fully rendered value study. Both are valid, depending on how much structure you want for the layers above.

If you plan to use layering in acrylic painting as your main technique, a detailed underpainting pays off more. If your approach is loose or painterly, a simple imprimatura is usually enough.

Underpainting vs. Blocking In

These two steps are often confused, and the confusion leads to painters doing one when they need the other. They look similar on the canvas but serve completely different purposes.

Underpainting is about tonal structure. It uses one color (or a value range of one color) to establish light and dark before any hue decisions are made. Blocking in is about rough color placement. It lays down approximate hues across the composition, usually without precise value accuracy.

Some painters do both, in sequence. They underpaint first to lock in values, then block in color over the dried underpainting as a second preparatory stage before the detail work begins. This is common in realist painting where value accuracy matters more than speed.

If you have ever blocked in colors and then found that the painting felt flat or lacking depth — that is usually a value problem, not a color problem. Contrast in painting comes primarily from the tonal structure underneath, not from the colors placed on top.

The quick test: convert your painting to grayscale. If it looks flat in grayscale, adding more color will not fix it. That is the point at which underpainting would have helped.

Acrylic Underpainting for Oil Painting

Using acrylics as an underpainting layer beneath oil paint is one of the most practical cross-medium techniques available to painters. Acrylics dry rigid and stable in under an hour. An oil underpainting in the same color might take three to five days to cure before it is safe to paint over.

The structural logic here comes from the fat over lean rule. Acrylic paint is water-based and dries through evaporation, making it inherently lean. Oil paint dries through oxidation and sits higher in oil content, making it fat. Fat over lean is exactly the order you want: lean acrylic underneath, fatty oil layers on top.

Fine Art Tutorials notes that lean paint dries faster and creates a more absorbent surface, giving subsequent fatter layers something to grip. This is precisely why the acrylic-then-oil combination works structurally, not just as a time-saving convenience.

What to do:

• Apply the acrylic underpainting in thin, diluted layers
• Let it dry completely before applying any oil paint on top
• Keep acrylic layers lean — thick or impasto acrylic under oil increases cracking risk over time

What never to do: paint acrylics over dried oil paint. Oil creates a flexible, low-adhesion surface. Acrylic paint dries rigid and will not bond to it properly. Alabama Art Supply confirms this directly: you can use acrylics under oils, but never oils under acrylics.

Artist Dimitra Milan of Milan Art Institute uses this approach in her layered mixed-media works, starting with acrylic and ink as the lean foundation before building richer, oil-based upper layers. The result is a stable paint structure that holds up across temperature and humidity changes.

For painters interested in exploring further oil painting techniques, the acrylic underpainting workflow is one of the lowest-risk ways to start working between mediums. The main thing to watch is layer thickness. Keep the acrylic base thin and the oil layers get a clean, fast foundation to work from.

Understanding how oil painting handles layering differently from acrylics also helps here. Oil paint remains workable and moves during curing for months. Acrylic locks down fast and stays put. That difference in behavior is exactly why the order matters.

When to Use Underpainting (and When to Skip It)

Underpainting is not for every painting or every painter. Knowing when it earns its place in the workflow and when it just adds time is actually useful.

Subjects That Benefit Most

Complex, detail-heavy subjects are where underpainting pays off most clearly. Portraits especially. The challenge of painting realistic skin tones is easier when the light, mid-tone, and shadow structure is already mapped in a single neutral color before any flesh tone gets applied.

Best candidates for underpainting:

• Portraits and figure work with complex flesh tones
• Still life painting with strong directional lighting
• Realist landscapes with deep spatial recession
• Any composition where chiaroscuro effects are a central goal

The school of realist art notes that the indirect painting method, which relies on a tonal underpainting followed by color glazes, is better suited to complex subject matter and beginners who benefit from solving one problem at a time.

When to Skip It

Loose and gestural styles generally do not need underpainting. Alla prima painting builds directly onto canvas in one session, wet into wet. Adding a structured underpainting to that workflow slows things down without meaningfully improving the result.

Same logic applies to abstract painting techniques where spontaneity and surface texture drive the work. A tonal map underneath an abstract canvas adds constraint where the style benefits from freedom.

Skip underpainting if: your style is alla prima, wet-on-wet, or loosely gestural. The imprimatura (a thin transparent tone over the whole canvas) is often enough to kill the white ground without committing to a full value study.

Underpainting for Beginners

Underpainting genuinely helps beginner painters, not because the result looks better immediately, but because it trains the eye to see value independently of color. That separation of problems is exactly how most painting courses teach the fundamentals.

The Virtual Art Academy’s alla prima guide makes an interesting observation: even plein air painters who work quickly sometimes apply a minimal imprimatura for the dark masses before jumping into color. That partial underpainting approach works well for beginners who want the structural benefit without the time cost of a full grisaille.

Beginner recommendation: start with a monochromatic raw umber wash. It dries in 15 minutes with acrylics, gives you a clear value map to paint over, and is transparent enough that mistakes are easy to fix. The learning payoff is high and the risk is low.

According to Industry Research data from 2023-2024, educational purchases accounted for nearly 23% of art paint volumes in developed markets, reflecting the growth of structured painting instruction where foundational techniques like underpainting are increasingly central to curriculum design.

If you are just starting out, understanding tone in art first makes underpainting much easier to apply with purpose. And once you are comfortable with acrylic painting techniques more broadly, underpainting becomes a tool you reach for selectively rather than a required step for every canvas.

FAQ on What Is Underpainting In Acrylic Painting

What is underpainting in acrylic painting?

Underpainting is a preliminary paint layer applied before final color. It maps out tonal values, light, and shadow using a single diluted color. In acrylics, it dries fast, making it a practical first step for building value structure before committing to full color.

What is the purpose of underpainting?

It separates two difficult problems: value and color. By establishing lights and darks first, you make better color decisions in later layers. It reduces overpainting, keeps the paint surface clean, and gives transparent colors something meaningful to interact with visually.

What colors work best for acrylic underpainting?

Raw umber, burnt sienna, and Payne’s gray are the most common choices. Raw umber sits neutrally under almost any color. Burnt sienna works well for warm subjects. Payne’s gray suits cooler, high-contrast compositions like dramatic landscapes or night scenes.

What is the difference between grisaille and imprimatura?

Grisaille is a full value study in gray tones, modeling form with lights and darks. Imprimatura is just a thin transparent wash over the whole canvas to kill the white ground. Grisaille takes more time. Imprimatura is quicker and suits looser painting styles.

Can you use acrylic underpainting under oil paint?

Yes. Acrylic under oil follows the fat over lean rule correctly. Acrylic is lean and dries rigid fast. Oil layers go on top fat and slow. Never reverse the order. Painting acrylics over dried oil creates adhesion failure, as acrylic will not bond to an oil surface.

What is verdaccio underpainting?

Verdaccio is a greenish-gray underpainting mixed from black, white, and yellow ochre. It originated in Renaissance art and works as a complementary base for flesh tones. The green neutralizes warm skin pigments, producing more luminous, realistic results than flat mixed flesh color alone.

How thin should acrylic underpainting be?

Thin enough to be slightly transparent. Dilute with water to a wash consistency that flows easily but still holds some pigment. Too thick and it becomes hard to overpaint. Too thin and it offers no tonal information. A mid-value wash is the practical target.

Do beginners need to underpaint?

It is not required, but it helps. Underpainting forces you to solve value before color, which is how most painting fundamentals are taught. A simple raw umber wash dries in minutes with acrylics and immediately trains the eye to read value scale before color complexity enters the work.

When should you skip underpainting?

Skip it for alla prima, wet-on-wet, or loosely gestural work where spontaneity drives the result. Abstract painters rarely need it. A thin imprimatura is usually enough to remove the white ground without committing to a full tonal study that would slow the workflow down.

Does underpainting color affect the final painting?

Yes, noticeably. Warm underpaintings push final colors toward warmth where the base bleeds through. Cool ones add atmospheric distance. A complementary color underpainting creates visual tension at color edges. Choosing your underpainting color without thinking about your top layers is a mistake that shows up in the finished work.

Conclusion

This conclusion is for an article presenting the full scope of acrylic underpainting, from grisaille and verdaccio to monochromatic washes and imprimatura.

Each technique serves a different purpose. Grisaille locks in tonal contrast. Burnt sienna and raw umber washes build warm, transparent foundations. Verdaccio handles flesh tones with a precision flat color mixing simply cannot match.

The fat over lean rule makes acrylics a reliable base for oil painting process work too. Thin acrylic layers dry fast, adhere well, and give oil paint a stable surface to build on.

Whether you are working on portrait painting or a complex landscape, the principle stays the same: solve value structure first, then color.

That single shift changes how every subsequent layer behaves.