Acrylics were originally promoted and are still often chosen as an ‘easy’ alternative to oils. Discover how oils can be a natural next step for experienced acrylic painters.

Martin Kinnear begins with an admission, ‘I love acrylic paints; there you are, I’ve said it. I teach and paint exclusively in oils, but I’ve always had a soft spot for acrylic, and have even undertaken consultancy work for acrylic manufacturers. I like acrylics because they are the great survivors. You can drown them in pints of water, stuff all kinds of odd substances and textured bits into them, or slap them on with a trowel, and they’ll still ‘work’, after a fashion.

‘What you shouldn’t do is use them as an underpainting medium for oils. I know, everybody does it, but please don’t. Acrylics are brilliant and oils are fantastic, but for lots of technical reasons, it’s best to keep them apart. I know oils need a short ground to dry and a luminous base to glow, and acrylic underpainting promises both of these. But, still, please don’t do it. Acrylics are wonderful paints, as are oils, but they all do different things’.

Sea Study, oil, (76x102cm). Try as I might, I couldn’t achieve this translucent depth with acrylic.

Oil or acrylic? Discover the similarities and differences

Colours and colour-mixing

Acrylics shares the same pigments with oils so, if you’re an experienced acrylic painter, all your familiar and favourite colour mixes will translate straight through to oils. But in addition, you’ll have more choice, as oil ranges are generally more comprehensive than acrylics, and often contain classic Old Master colours, which never made it into such a modern medium.

Whether you stick with the pigments you know or try new ones, colour mixing with oils will actually become easier, because they stay ‘open’ (mixable and blendable) for far longer than normal acrylic. This means that you can start an area (or ‘passage’) of oils with a given mix then adjust it on your palette without worrying about it drying or fiddling with retarding mediums as you work.

Starting a mix from a simple colour you can then extend it into tints, shades and saturation or temperature variants as you go.

Example

From a simple blue (far right), you can add white (tint), black (shade), violet (warm blue, see top right), green (cool blue, see bottom right) or orange (desaturated blue, see left) and, once this mix is on your palette, you can paint for hours in the knowledge that you can always come back to it and pick up more over the course of the session.

Acrylics don’t offer this same convenience, and it can be difficult to make precisely the same mix when you need to make a fresh batch of paint.

This facility to keep oils open over an extended working session is their greatest advantage over acrylics. Although it’s possible to extend acrylics with mediums or buy acrylics that can be re-wetted (‘interactive’ acrylics), it’s far more intuitive to paint straight through from a few simple mixes.

If you are a fan of painters who lay out premixed palettes of colours, oils allow you to pre-mix a range of colours before you get into the messy business of painting, without worrying about them drying out. This allows you to concentrate on placing rather than mixing colours.

The benefits in summary

The first and most important benefit of moving to oils is how much easier you will find keeping your palette mixes and canvas blends in hand.

Blocking in – a different approach

The great advantage of oils staying wet, however, is also the biggest challenge for experienced acrylic painters to overcome. Simply put, the tried-and-tested acrylic method of letting it dry and painting over it after 20 minutes just doesn’t work in oil. If you try this, you’ll make grey mud. The answer, of course, is to modify your approach. Rather than plaster wet paint everywhere and work over it after a leisurely cup of tea, just put each colour more or less where it needs to go then gently blend them together.

Oil painters call this method blocking in, it’s a useful technique and the basis for more complex things.

Mediums – to use or not to use?

Acrylic mediums are legion; from texture gels to mica flakes, you can have it all.

So how do oils compare? The answer to this lies in the nature of the acrylic binder itself. Essentially it’s a flexible liquid plastic, into which you can add pumice, sand, mica, sawdust or more or less anything that comes to hand. Oils just don’t work like that. You can put various sands, chalks or silica (ground glass) in them, and artists such as Turner occasionally did, but to do so routinely is to miss the point.

The true beauty of oils lies in their lustre and clarity so if you intend to mix them with fillers, glass beads or pumice, acrylics really are a better choice.

Nothing looks like an oil. Acrylics can be bright in a saturated sense, but they just don’t glow with an inner light in the way that oils can, and it’s this potential to look a little more optically complex, which gives great acrylic painters the impetus to try oil.

Study after Turner, oil, (76x102cm). If you like expressive, creative paintings that glow, oils are the paints for you.

How to glow with oils

Because acrylics dry so rapidly, many acrylic artists place their paint fairly thickly, but if you use this method you won’t be making the most of your oils.

If this sounds like you then simply apply a number of thinner, more translucent layers to achieve the depth of colour, rather than fat impasto brushstrokes. This allows more light into the painting, and lets reflected light from the gesso to make it glow.

The principle of using several thin, translucent layers is a common approach in oil where thin layers are preferred instead of fat impasto, because they dry and look so much better.

You can add textured impasto to oils, of course, but as a rule of thumb only do it on a few finishing strokes.

Demonstration: After Seago

Study after Seago, oil, (51x76cm)