Underpainting in Oil and Acrylic

Every artist knows the intimidation of a blank white canvas staring back at them, and underpainting is the perfect solution when deciding where to start. As a technique first utilised by the Old Masters, it underpins Renaissance painting, and lies quietly beneath masterpieces. Some have considered these traditional methods stifling, restrictive to the spontaneity that happens on canvas without a tight plan. But it’s important to consider that the definition of an underpainting is flexible and personal. It can be as simple as a coloured ground with a few lines, or as complex as a fully realised tonal study.

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What is Underpainting?

Simply put, underpainting is the first layer of paint applied below a finished painting, to give structural and tonal direction to the beginning of the work. This initial layer can be completely obscured or allowed to shine through depending on the artist’s intentions, and can be utilised in both oil and acrylic paints. Underpainting can be as brief or complicated as you desire — it’s about utilising it to best support your own practice.

 

 

The Origins of Underpainting

Underpainting has existed since oil paints were first used in European painting in the early 1400s. Jan Van Eyck is recognised as a pioneer in the alchemy of oil painting, and we can see him using the first examples of glazing in works such as The Arnolfini Portrait in 1434.

 

 

From then on, it was adopted by the Masters of the Renaissance, and Titian is believed to have made some of the first opaque tonal underpaintings, with softer, less defined edges to allow for invention outside of the central motifs. It was embraced all over Europe, by figures like Da Vinci, Rembrandt, and Rubens.

There are many names for the traditional types of underpainting based on the colours used. A brown underpainting is referred to as brunaille. A mixture of black, white and yellow pigments resulting in a greyish green or brown neutral tone was known as verdaccio, or the dead layer, as it does little to affect the final palette of the work. Grisaille is perhaps the most well known as it was used by the workshops of the Masters’ to replicate the preparatory drawings they were trained to reproduce, in greys through to blacks.

 

 

Classical and Contemporary Methods for Underpainting

Most underpaintings are monochromatic and begin with a coloured ground, which is colour applied as an even layer across the surface. The artist may leave out or remove highlighted areas to allow the white beneath to show through, giving the final work a greater sense of light and contrast. This first stage is traditionally known as imprimatura. Next the structure of the painting is blocked in, in increasingly darker layers, and developed to the level of detail that the artist wishes. In this example I have painted the same portrait with a Masters’ style underpainting, and then in a looser style I would use myself.

 

 

On top of a traditional underpainting, glazing was utilised to add colour to the work. Glazing is the application of paint in thin, transparent or semi-transparent layers. When built up over applications, it results in a glowy, unified surface.

Since the pigments are applied in separate layers and allowed to dry, they appear to be mixed in the finished work to our eye, but are actually separate on a chemical level.

Since the pigments are applied in separate layers, they appear optically mixed to our eye, but chemically are not. This makes for a very even, stable, durable surface.

Using this method, underpainting is still very much part of the painting, and shines through to the finished surface. This technique doesn’t allow for much improvisation, so it’s most suitable for pre-planned work.

 

 

This is not the only way to utilise underpainting. Completely covering this first layer and using it simply as a placement guide is a useful method too. I find that a combination of both approaches gives the painting a dynamic finish, with more translucent areas paired with opaque ones. There are plenty of paintings where the original underpainting is nothing like the finished work, and I think feeling the freedom to abandon it completely is sometimes necessary. For the spontaneous artist, the underpainting can be seen as the beginning idea, before the complete one emerges.

 

 

 

 

The Benefits of Underpainting

The benefits of underpainting should be felt primarily by the artist using it, and be tailored to their personal needs. It is a very versatile technique and should be considered in broader terms than the Old Masters method.

Allowing the underpainting to shine through to the finished surface can create a desirable effect which would be impossible to recreate by painting alla prima. Having an image beneath or beyond the surface is simply not achievable once the surface is made opaque with colours. In this sense underpainting is not only a tool but a stylistic choice.

 

 

For those desiring a flat, smooth, finished surface, highly rendered underpainting and glazing is the best technique to achieve this. Even for the kind of painter who relishes texture and brush marks, all artwork boils down to composition, and underpainting is a key tool for figuring out a good one before committing to detail.

Figuring out the tonal values in your work can be difficult with a broad palette, so being able to block them out with one colour before beginning makes the process much easier.

Some artists will work out their composition on their surface as a line drawing with pencil or charcoal before painting, and although this can be helpful in terms of control, sometimes these lines can show through, or mix with your paint and dull it. I think it’s important not to distinguish too heavily between drawing and painting, and applying paint as if it’s a line drawing makes for a useful underpainting, without the annoyance of muddying that can come with dry media. Using an underpainting doesn’t mean it has to be painterly if this is a concern.

 

 

Choosing a Colour and Method

When choosing a colour for your underpainting, it is essential to consider the content of the work, the mood you’re hoping to convey, and the palette of the rest of the work. The colour chosen for the underpainting has a great impact on the final work, even if it isn’t obviously left visible. In the Masters tradition, a brown or grey underpainting was utilised to be non-invasive to the final work, and provide a versatile framework for vibrancy to be established later. These colours were also the most affordable in their time, so it made sense to use them for the base stages.

But the opposite approach can also be taken, where a vibrant colour may immediately establish the direction of the work. When envisioning the palette of your finished work, choosing a complementary colour for the underpainting can add a lot of visual drama. For example, many portrait artists paint on top of a green underpainting, so that warm, reddish flesh tones bounce from it.

If high contrast isn’t what you want, choosing an analogous colour (next to each other on the colour wheel) for your underpainting may be the solution. This can be especially useful if you want a harmonious finish, and generally makes for a calmer mood.

 

 

 

 

The mood of the finished painting must also be considered. If you’re aiming for a sombre feeling, a cold colour will instantly chill all the colours you add on top — and vice versa for creating a comforting, warm environment.

A multi-colour underpainting can be useful if you want to take advantage of various base colours on one surface. Favoured by the likes of Titian and Giotto, I find this approach to be very useful if you’re certain about the zones of colour you want to establish. It also removes the problem of the underpainting potentially dulling your later layers, when they’re only supported by the same or similar pigment below. However, this is another method that can be restrictive if you change your mind later on.

 

 

For any brightly coloured underpainting, I’d suggest creating a separate sample test of how your colours sit on top before you start. On some highly chromatic colours, other colours can grey and look dull, so it’s important to test out your palette.

 

Underpainting in Oil

Underpainting in oil paint is extremely forgivable, as the slow drying time allows for adjusting, wiping away, and a much slower decision making process. To add highlights back into the surface, you can simply rub a rag with some solvent onto the area you wish to lighten.

 

 

 

 

It’s important to remember that you can only apply oil on top of an oil underpainting, since applying acrylic on top would eventually crack and flake off because acrylic doesn’t adhere to oil.

The mixture of medium you are painting with is very important in oil underpainting, so that a reasonable drying time and adhesion to the surface happens without disturbing your previous layers. In general, oil underpaintings begin with a much larger proportion of solvent and a small amount of oil. This makes the paint dry faster, and less slick, so that future layers will attach properly.

Pre-mixed oil painting mediums may also be useful for this purpose, as long as you remember the ‘fat-over-lean’ method. This means that the initial layers of a painting should be ‘thinner’ (less oily) than the later ones, making them ‘fatter’. If you make an underpainting with an oil-heavy medium, it will take a long time to touch dry — potentially weeks — and may slip and slide during this time. Even when dry it may have too much sheen to hold future layers properly. But if applied properly, an oil underpainting will make a durable base for a painting that will last. For my oil underpaintings seen here, I used a mixture of 1:6 linseed oil and turpentine.

When glazing oil on top of an oil underpainting, the previous layer must be dry before you apply the next one, or the paint will shift, or may dry at different rates making it unstable. As I described above, you should work ‘fat-over-lean’ when glazing too, so your final layers will have an increased amount of oil and therefore dry down with sheen.

 

 

It’s also important to select paints that aren’t opaque so they don’t cover your work, signified by an open square symbol on paint tubes. From left to right, these Jackson’s Professional Oil Paints are transparent, semi-transparent, semi-opaque and opaque. I’d recommend sticking to the transparent and semi-transparent colours for a subtle, buildable effect.

 

 

 

Underpainting in Acrylic

An underpainting in acrylic can be used underneath acrylic or oil paint, and has a rapid drying time. This makes acrylic perhaps the most versatile underpainting material. Nonetheless, once acrylic has dried down it is impossible to move, unlike oil can be with solvents. Trying to lighten dried areas with water won’t have any effect, so you may have to introduce white paint to any mistakenly darkened areas. This doesn’t give such a seamless effect as the white ground of the canvas showing through, and may result in unwanted ridges of texture. My advice would be to apply the acrylic underpainting in thin, watery layers, giving you the ability to still make corrections with little texture. Don’t worry too much about mistakes or omissions in acrylic underpaintings, and focus on correcting them on the surface of the work.

Being able to use acrylic paint underneath oils is advantageous, as you don’t have to worry about colour leakage, long drying time, or measuring solvent ratios. It is my personal favourite method so I can start on the oil layers on the same day.

 

 

 

Using an acrylic underpainting for an acrylic painting is also helpful. You can still establish some depth with washes if you’re working on canvas or board, though without as deep of a finish as oil glazing. I find that abandoning the underpainting is easier with acrylics, as they can be applied to obscure your previous work very easily without bleeding through. I also enjoy using an acrylic underpainting in some of my drawings, or mixed media pieces, as later applying dry media is completely stable. This is especially helpful for use on paper, and even when used subtly can give work a new dynamism.

 

 

 

 

 

Underpainting in oil and acrylic is a versatile technique for all kinds of painters. The benefits of traditional underpainting are experienced most by those who wish to have a seamless finished painting surface. A flat, clean face to the painting can be exceptionally beautiful, but it isn’t necessary for all artists. If you enjoy the texture and spontaneous build up of paint, underpainting should be a tool you use to briefly help yourself construct the painting, instead of a guiding hand.

All painters should consider underpainting in oil and acrylic as a tool they can choose to use to their own extent. Understanding the process and its benefits can be seen as part of a problem solving process, rather than dictating the final answer.

 

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Further Reading

Colour Mixing: the Atmospheric Quality of Cool Colour Palettes

How Oil Painting Mediums Work

Acrylic Painting for Beginners – What You Need to Get Started

Everything You Need to Know About Oil Painting Paper

 

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