How Acrylics can be Used with Oil Paints

There are two types of artist paints: oil based and water based. Although the two do not mix, some water based paints can be used in an oil painting. But some of the latter should never be used with oils. This begs the question, what are the main types of waterbased paints and which can be used with oils?

What Defines Water Soluble Paints

There are several types of water soluble paints for artist use, but all have one thing in common: they can be thinned and manipulated by the addition of water. Oil-based paints cannot be thinned with water (except for watermixable oils), only spirits. Water-based paints dry by transpiration, which takes around an hour or so. But here is where the commonality ends.

Types of Water Based Paints for Art

Watercolor paint consists of pigment tablets (sometimes in the form of watercolor pencils) that release pigment by the addition of water. Delicate washes can be achieved, as well as high detail if used neat. However, the paint remains workable if water is reapplied onto it, so it never dries water-resistant. For this reason, watercolors are often mounted behind glass or protection. Gouache can be used in conjunction with watercolors, but is more opaque by nature, as the pigment is bound into gum Arabic.

However, as neither dries into a tough, watersoluble paint layer, they would not be suitable for use with oils. But acrylics would be ideal. Acrylics can be applied opaque or in washes. Like oils, acrylics can be applied onto canvas, wood or board. But how can acrylics be used with oils?

Acrylic Underpainting for Oils

Acrylics and oil paints do not mix in themselves, but acrylics can be a useful medium for providing the underglaze for an oil painting. Underglazing is the application of a paint layer that forms the foundation onto which the upper layers of paint can be applied. Underpainting is explained in a separate article here, but for now, I shall explain how the acrylic paint can be used to set the tone of the oil painting.

Acrylic Based Underpainting

The underpainting (also known as an imprimatura) is traditionally thinned oil paint, that can take a few days to dry, but acrylic paint takes a mere hour or so. Acrylic paint (also used in acrylic primer) provides extra protection for the art surface from the oil in the paint. As acrylics can provide an opaque paint layer or a glaze, it offers the artist a choice on the sort of imprimatura to use. The imprimatura kills the offputting whiteness of the art surface or can be used to help the artist judge tones and to inject a chromatic undercurrent throughout the painting.

Types of Acrylic Paints

There are several types of acrylic paint the artist can use, all of which would be suitable for the underpainting, but for informative purposes, these are: artist acrylic such as Finity. These offer high tinting strength and coverage. The hue also shifts very little between wet and dry, as the resin remains transparent between these two states. Galeria offers almost the same qualities at a more affordable price but is a little runnier, for covering large areas. Again, Daler Rowney’s System 3 can be found in large tubs for the same purpose.

Liquitex acrylic paints are heavier in body, for opaque coverage and a silky texture, rather like oil paints itself. However, it can be thinned into glazes when required.

How to Use Acrylic Paint for Oils

For best results, apply the underpaint in a thin, even layer, not as impasto, or this will result in unwanted lumps beneath the oil paint. More than one glaze layer can be applied to increase depth of color. However, allowing the white art surface to ‘glow’ beneath the glaze will help inject life into the oil painting. Allow the acrylic layer to dry thoroughly before applying the oil paint.

Take note, acrylic is an ideal medium for underpainting an oil painting, but should never be used on top of the oil painting. As acrylics dry in a plastic-like film, it could flake away from the smooth nature of dry oil paint. Also oils dry must slower than acrylics, which may cause the acrylic paint to crack over time.

Acrylics in Oil Paintings

Acrylic paints can be used in an oil painting if applied properly. The two of course do not mix, but acrylic paint is the ideal underpainting medium for an oil painting. Acrylic paints really come in three types: artist quality, heavy body and runny. The heavy body acrylic paint will provide high coverage; the runnier type will cover large areas more easily. Different types of underglazes can be applied with acrylic paint depending upon the translucency of the glaze used, but never use watercolors or gouache instead of acrylics, as these do not provide a stable, tough and water resistant paint layer once dry.
 
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