OIL PAINTING GUIDES
Painting techniques using oils: tips for beginners
I want to dispel the myth that painting in oils is particularly difficult – it isn’t! And it is well worth the reward, because in my opinion oil paints are so much nicer to handle and better in final appearance than fast-drying acrylic paint. But there are one or two simple rules to follow to ensure that your painting stands the test of time. Here you’ll find a step-by-step introduction to the basic techniques.
CHOOSING AND PREPARING YOUR CANVAS
If you visit an art shop you will have the option to buy one of the following options: a traditional chunky ‘stretched canvas’, a thin ‘canvas board’ (or ‘canvas panel’) which consists of canvas stuck down to a strong card panel several millimetres thick, or a pad of ‘canvas paper’ which is a thick paper able to take oil paint and imprinted with a canvas-like texture. Canvas paper is suitable for sketching in oils rather than for producing a finished painting to be framed and hung on a wall, although it is an economical way for a beginner to practice. Canvas board may be preferable to a stretched canvas if you like its firmer feel, or if you want to transport it around for any reason as it is a lot less bulky.
Whichever canvas choose make sure it is fully pre-prepared – that is to say that it has been SIZED and PRIMED. You’ll find a full explanation of sizing on my oil painting materials page and why it is so important. Fortunately art shops sell already primed and sized canvases and canvas boards so you have no need to do it yourself. These will come ready prepared with a nice white surface to paint straight onto. ‘Canvas paper’ pads will also be coated with a priming layer and ready to work onto. The point of sizing is to seal the porous surface of the canvas and prevent the paint and its acidic qualities from penetrating and eventually rotting it, causing the paint to flake off. If you work onto an un-sized canvas then your creation will have a limited lifespan.
Size was traditionally made with rabbit-skin glue (still sometimes used) followed by a priming coat of white lead undercoating paint. These days you can still buy separate size and primer, but an easier option is to apply ‘Acrylic Gesso’ which does the job of sizing and priming all in one. You can buy it yourself if you ever get on to making your own canvases. Although known as ‘acrylic’ gesso they are suitable for preparing a canvas for either oils or acrylic paint. Meantime, buy the pre-prepared canvases that art stores supply. You can check on the label that they have been ready-sized and primed for you.
Below, Atlantis oil primer and how it’s applied to a plain sized canvas, and some pre-sized and primed stretched canvases
PAINTING ONTO BOARD:
If you want to paint onto a hard board rather than a canvas, you can certainly paint onto an MDF panel – for instance – but you will first need to prepare it using a pot of the Acrylic Gesso mentioned above. Some brands are specifically formulated for painting on wood and sold as ‘Acrylic Panel Gesso’. Others are supposed to be suitable for either canvas, or board. Use as many layers as advised with the instructions on the side.
MEDIUMS FOR DILUTING YOUR PAINT
So you have purchased your pre-primed canvas and opened your paint tubes, and squeezed some paint out onto your palette ready to mix together. It may be that you like the texture of the paint as it comes out of the tube and are happy to apply it to the canvas as it is. But more likely you will want to dilute it a little first. And either way, you are going to need to clean your brushes in something in between colours. Since oil paint isn’t soluble in water, you are going to have to use something else to dilute your paint and clean your brushes.
What you will need to use are ‘mineral spirits’. These come in a wide range of mediums, and you can read a lot more about them here › To summarize however, I’d advise that to dilute your paint and to clean your brushes you should use Artists’ Mineral Spirits or Artists’ White Spirit. This is an alternative to the traditional (but rather toxic) Turpentine, and is basically the same thing as DIY store White Spirit but with the impurities removed. DON’T BE TEMPTED TO USE REGULAR WHITE SPIRIT! It is cheaper, but those impurities will destroy your painting, preventing the paint from ever fully drying. Certainly do not dilute your paint with it, and I don’t even recommend cleaning your brushes with it. If you want to economize, try using water mixed with detergent to clean them. Give them a quick soak in some Artists’ Mineral Spirits first, to help loosen the paint.
The other types of mediums you will use to dilute your paints are oils. Again you can read more about these on this materials for oil painting article. But briefly – I would recommend using Windsor and Newton’s ‘Liquin Medium’ (above, right), which is suitable for both dark and light paint, and speeds up drying. If you don’t want to speed up drying you might use plain Linseed Oil, or Poppy Oil for lighter colours (Linseed can be a bit yellowing).
Why do you need to dilute your paint with an oil medium as well as mineral spirits? Well, it is okay to use a little mineral spirits to loosen your paint. But if you use too much then your paint will loose all its’ shine and viscosity. It will become very thin, preventing you from painting with thick brushstrokes, if this is what you want. Oil paint, as it comes in a tube, is a mixture of pigment and an oil binder to fix it as it dries. Take away too much of the oil and not only do you lose shine but the paint can’t oxidize and set properly and may eventually flake off. So as you add Mineral Spirits, add some drops of oil too.
Why not use JUST oil to dilute your paint? You can do this, but the more you add the shinier your paint will get and you might not like the look of that either. As we will read further on, it is important for the preservation of the painting to get the balance of spirits and oils correct in the lower and upper layers.
APPLYING YOUR PAINT
To make sure your painting will last the test of time, there are three main rules to follow.
RULE NO. 1 Always work on a primed canvas (or other surface)
We have already covered this above. I have seen some paintings disastrously ruined by painting onto a non primed surface! Their paint may entirely flake off. Buy a pre-primed canvas and you will be fine.
RULE NO. 2 When diluting your paint with spirits, add some oil to balance them.
If you dilute your paint with a spirit thinner, either because it is too thick or just because you have cleaned your brush in it a lot and then dipped it into your paint repeatedly, make sure you add a drop or two of oil as well. This is because if you add a lot of Turpentine, Artists’ Spirits or other thinning medium to your paint, it may no longer have enough oil in it to bind the pigment. In which case you need to add some more oil, in the form of Linseed oil, Poppy oil, or a product such as ‘Liquin’. Once you’ve started, you’ll find it easy to get the balance right. You’ll know when your paint has the right glossy look about it. If it is looking really ‘matt’ once it is dry then you know you need to be adding more oil. If you’ve added too much oil there isn’t much harm in it (apart from on the bottom layer…see below) but it might look shinier than you want it to.
RULE NO. 3 Follow the ‘Fat Over Lean’ Principle
The well-known ‘fat over lean’ rule simply tells you that it’s not a good idea to make your first layer or two very thickly, and then put thinner paint (diluted with thinning mediums mentioned above) above it. This is because when you apply thicker paint pretty much straight from the tube to the bottom layer, the oil content in it will cause it to move and contract as it dries. If you also have a thinner, diluted layer above it this contraction will cause the thinner paint on top to crack. Additionally the thicker bottom layer with the most oil in it will dry more slowly than the thinner layer above, exacerbating the problem because it will continue to move after the top layer has dried and stopped moving. Oil paint takes literally decades to dry! It may appear dry to the touch after a few days, but it doesn’t finish the chemical processes of oxidization and become fully stable for many decades.
You could therefore rephrase the rule like this: the closer to the top the layer of paint, the thicker you should apply it and the more oil you should have in it. Upper layers should have at least the proportion of oil in them that they had when they came out of the tube, and if you have added thinners to them then add some oil too, to compensate. The lower layers should have less oil in them and be applied more thinly than the top layers.
Some historical painters put thin layers of coloured ‘glazes’ (mostly oil and a little bit of paint) on the very top to create shimmering effects – for example when painting drapery. This was okay even though the layers were pretty thin, because they were predominantly oil in their content and therefore remained very flexible and able to survive the movement of the layers below. If you want to use your paint to apply translucent upper layers in thus way with a lot of oil and a little bit of paint, use Stand Oil which is thickened Linseed Oil. It has a thick consistency and will dry smooth without leaving visible brushstrokes.
Now of course, you may not want to work in lots of layers. You might want to work with only one, which is fine. However it’s more likely that you’ll want to apply your paint in a few layers, because with only one layer, you’d probably find the original white colour of the pre-primed canvas showing through in a way you might not like. So just remember: thinner layers at first and thicker layers on top, and don’t dilute your top layer(s) too much using thinner.
Here’s a useful video describing the ‘fat over lean’ rule.
Thick ‘Impasto’ Painting
If you want to apply your paint really thickly, buy some Impasto Medium to mix with it. This will allow you to paint as thickly as you like without risk of your paint eventually cracking, and with your brushstrokes preserved and visible as with this example from a Van Gogh. Impasto Medium is not the same as Stand Oil which is used to thicken paint and make it more oily, but will also flatten brushstrokes. Instead Impasto Medium is design to make the paint stand in thick peaks, like icing or frosting. It comes in a tub or in a tube.
What to use for your base layer of paint
As I mentioned, a pre-primed canvas will be brilliant white in colour, so you may want to begin your painting by either first blocking in large areas of colour (as below), or by applying a base layer of one particular colour to the whole canvas. The major advantage of this is that when faced with a bright, white canvas, you may find it hard to judge the tones you want to put down – whereas if you start off with a canvas that’s painting in a mid-tone (say a brown, or bluey-grey) these tones become easier to discern. This is particularly the case if you are painting from ‘observation’. Historically, painters would not have started off with a white layer but rather a darker and richer tone. In the modern (and more abstract) era a white background became popular as it gives the paint on top the greatest vibrancy.
So – if you want to apply a base layer then follow the ‘fat over lean’ rule above and apply a reasonably thin layer of paint, using a stiff and fairly dry brush to spread it well over the canvas. Another reason for applying a first layer thinly is that you don’t want to have ‘ridges’ in the paint when you come to begin your painting. If this happens, you can sand any ridges down with some fine-grade sandpaper once it’s dry. It might be worth adding a drop or two of ‘drying oil’ to your first layer (but not TOO much – you don’t want your bottom layer too oily, as we have discussed above). You’ll find that the first layer of paint takes the longest time to dry, and each subsequent layer will dry more and more quickly. This is because when applying later layers the oil in them will sink down and be absorbed by layers below.
A note about any white paint used in your first layer
Our main concern here is drying time. The first layer of paint takes the longest to dry, as I have just mentioned. Some white paint can take longer to dry than any other colour, so a white underlayer could take a good week to dry. Even if you’ve chosen a darker colour for your base layer, chances are it will have a fair bit of white in it. Generally for white paint these days we use either Titanium White and Zinc White. Titanium White is a nice, opaque white, but is extremely slow to dry. Zinc White dries a lot faster, but can cause cracking so do not use a lot of it in your under-layer.
However it’s now possible to buy a faster drying Underpainting White paint. Windsor & Newton and Daler-Rowney both make an ‘Underpainting White’ which is a mix of Titanium and Zinc pigments, with added texture to help the later layers of paint adhere. It has a faster drying time than using Titanium alone but won’t cause your upper layers of paint to crack.
USING YOUR PALETTE EFFICIENTLY
When putting out my paint on the palette I like to group my colours together (reds and yellows, greens, blues, and browns) and to keep these groups in the same places on my palette each time. This sounds a little over the top perhaps, but you’ll find that if you do this you’ll soon learn by instinct which part of your palette to look for the colour that you want and won’t have to search for the right colour constantly. It really saves a lot of time when you have many colours all over your palette! At the end of a painting session, if you want to keep the colours you have squeezed out or mixed up moist and workable, then cover them with Clingfilm (Saran Wrap) – as long as the air can’t get to them they won’t start to dry out. You can find more tips on how to reduce waste in my oil painting handy hints guide.
As mentioned above it takes years for oil paint to completely dry, but it will be touch-dry and suitable for painting over with the next layer after a day or two. Thicker coats of paint will dry much more slowly than thinner ones (whether they are thinner because you’ve spread the paint more thinly, or because you’ve mixed them with a spirit or oil to dilute them) And the first layer takes the longest to dry, whilst the later layers will dry with increasing speed as the oil content soaks into the layers below. However you’ll also notice that different colours take varying amounts of time to dry. Lighter colours seem to me to take much longer than colours with darker pigments in them. This is another reason to apply a mid-tone, slightly darker first layer.
Be aware that as mentioned in the section above, Titanium White takes a long time to dry. I use Titanium for upper layers, but for a first layer as mentioned above, I will use Zinc White – which dries a lot faster – with some drops of a drying oil, or an Underpainting White. To speed up the drying of all your layers you can use Drying Linseed Oil – this is good for mixing with most colours, although it can be a bit yellowing so may not be suitable for very light colours. Instead for lighter hues you may prefer to use Drying Poppy Oil. A more modern alternative which will not have any yellowing effect and is suitable to mix with any colour is Windsor & Newton’s ‘Liquin’ medium which also speeds up drying. You can find more information here about different drying oils.