OIL PAINTING – A Brief Overview of Materials and Techniques

 

There is a certain mystique about oil painting that can be off putting to those who haven’t tried it.  DON’T BE PUT OFF. This is a brief description of what various terms refer to. This is not a ‘how to’ guide, nor do I expect anyone to work through it and learn it – it is merely a reference or reminder. As with all things, the more you do it, the more you learn about it.

When you are starting buy the various starter sets (paints, brushes) – they are good and relatively cheap, a pad of disposable palettes, and a pad of oil painting paper, some Zest It and some rags…then you are ready to try oil painting.

Materials

Supports

A ‘support’ is the name given to a supporting surface for oil paint. It should be stable and able to accept whatever material and technique you wish to use upon it. Wood panels, stretched canvas, hardboard, canvas board, MDF, paper and cardboard, oil painting paper and metal are the most common supports. Weight, ease of use, portability and personal preference all come into choice of support.

  • Canvas – There are a huge variety of shapes, sizes, cloth weave and quality available readymade. Some are ready primed, some are not. Canvas is also available ready stretched on board. These are usually ready primed. There are stretcher pieces available so you can make a canvas to any size, and you could cover it in a variety of cottons, or linen. For most needs a ready prepared canvas is convenient and more than adequate.
  • Oil sketching paper – This is commercially produced paper which is ready primed, easy and convenient to use.
  • Hardboard – This is made from wood-pulp compressed into thin sheets. It is preferable to paint on the flat, shiny side rather than the textured side, but the surface should be slightly sanded to make it more receptive to paint. This is a good, cheap, light weight support and is commonly used.
  • Paper and Card – Good quality, rough watercolour paper can be used when covered in a thin coat of gesso primer to counteract its absorbency. Gesso primer can be bought in artists’ supplies shops. Paper can be given additional stability by being stuck down on a piece of board. Cardboard can attract mildew and fungus unless stored in very dry conditions.
  • Wood Panels – This was the first type of support used, largely to be replaced by canvas during the Renaissance. Hardwoods are more stable than soft woods and less likely to warp. Wood panels should be cut from well seasoned pieces of wood that are without cracks or knots. Panels from discarded furniture can be used.

 

Priming and Sizing

Should you wish to try different supports that need different treatments then you could investigate priming and sizing in more detail. Below is a brief description of both so you know what is being referred to should you see ‘priming’ and ‘sizing’ in any literature.

A primer is the first coat of paint applied to a support. Its main function is to prevent the colour from sinking in to the support. Oil paint can darken with age and a white primer helps to counteract this potential problem. Hardboard can be primed with a few coats of an acrylic gesso primer. Before the support is primed it should be sized. The best size is made from Rabbit skin glue which is available from artists’ material shops. Hardboard and other water resistant materials do not generally need sizing before priming.

 I would suggest that it is considerably easier to find supports that are ready primed and sized.

 

Brushes and Knives

Long handled hog’s hair brushes are traditionally used for oil painting. They come in three basic shapes: flats, rounds and filbert, all of which make a different kind of brushstroke. In terms of size of the brush head a no. 1 is the finest increasing in size to 12/14 and possibly beyond. Sable or soft brushes are mostly used for the finer detail. Experience will tell you which sort of brush you prefer. There are many mixed sets available which give you an opportunity to try different shapes and sizes relatively cheaply.

Brushes should be cleaned after use.  First wipe off excess paint on a cloth/rag, then rinse in turpentine, or petrol substitute. Degrease in washing up detergent. I put Fairy liquid on a scouring sponge, but this is a bit rough on most brushes. Rinse the brush thoroughly in warm water and reshape the bristles.

Palette knives are either flat or trowel shaped. They are mainly used for mixing and blending colour. They are useful for scraping back unwanted bits of painting. Some artists use knives to put paint directly on to a painting.

Palettes

Palettes come in a myriad of different shapes, sizes and materials and the final choice comes down to personal preference. Wooden palettes are usually made from mahogany or birch plywood. White plastic palettes are good for helping to judge colour; a piece of white paper under a sheet of glass works as well, but is less portable. Disposable palettes are convenient and light, but can waste paint at the end of a session. This sounds like the there is no perfect palette, but it is probably more the case that it depends what you are painting. Possibly a palette for mixing, set up on a table next to you, and a hand held palette to work from would be something near the ideal combination.

Paints

Oil paint is made from ground pigment in an oil binding medium. The oil reacts with oxygen in the air and it dries slowly to become a solid ‘linoxyn’. Oil paints are sold in air tight tubes so artists no longer have to grind the pigments themselves.

There are oil paints on the market that are somehow water soluble…I can’t really see the point of them.

Pigments used in paints are either natural, such as ochre, terre verte and ultramarine,  animal and vegetable, such as rose madder, indigo, sap green, and gamboges, or artificial chemical compounds such as cobalt blue, or cadmium red. Some paint colours are more transparent than others, some dry quicker, and some have greater body so are useful for impasto. Different brands have differing pigment concentrations – the more you pay often equates to quality in this regard. There are many starter sets on the market that are more than adequate.

Below is a quick guide to basic features of some colours. Don’t let this blind you – try different colours and refer back to this list if you need to. Some paints are more poisonous than others…don’t eat them, don’t mix with your fingers, and don’t use your arm as a palette – fairly obvious really.

  • White. All whites are dense and will stop transparent colours being transparent. Flake white is good for impasto, zinc white is bright but prone to cracking when dry, and titanium white is a good all rounder.
  • Lemon Yellow is transparent.
  • Chrome Yellow, opaque and not very permanent
  • Cadmium Yellow, more permanent than chrome yellow
  • Indian Yellow is brilliant and transparent
  • Naples Yellow, opaque
  • Cadmium Reds, range of colours, permanent and good covering power
  • Alizarin Crimson, intense, slightly transparent
  • Vermilion, opaque
  • Madder, mainly used as a tint for other colours
  • Indian Red, opaque
  • Carmine, transparent pinkish red, less permanent than other reds
  • Cobalt Blue looks transparent
  • Cerulean, opaque
  • Ultramarine, semi transparent
  • Viridian Green, transparent
  • Emerald Green, opaque, turns black when used with Vermilion
  • Raw Sienna, transparent

There are numerous other colours, tones and hues. The best way to discover their qualities is to try them. Paint tubes are marked with their degree of permanence.

Paint additives

All oil paints produced in tubes contain a certain quantity of poppy, or linseed oil. Some artists use paint direct from the tube. Mostly it is more practical to thin paints.  There are three basic ways of doing this: add more oil, add varnish, or add an evaporating essence such as turpentine or an odourless substitute such as Sansodour, or Zest It.

The common rule of thumb is that one should paint from thin to fat, i.e. start a painting using paint with a large amount of thinner and over painting with less and less thinner. If one puts a thin paint layer on top of a ‘fat’ paint layer the fat layer dries at a slower rate and cracking will result.

There are various special mediums one can buy to speed up and retard the drying process of the paint. A mixture of linseed oil and turps/zest it is a straightforward combination for everyday thinning. Some linseed oil is yellower than others, some dries quicker than others. This could be relevant to a painting with whites and pale yellows. Poppy oil is pale and none yellowing.

Don’t get too complicated about which thinner to use initially. Zest it won’t give you a headache whereas turpentine will. Don’t use white Spirit except to clean brushes as it dulls the paints.

Varnish can be used as part of the painting process mixed with turpentine and oil, or as a protective film for a finished picture.

NOTE: Paint pigment must be absolutely dry and dust free before applying varnish

  

TECHNIQUES

 

The way one uses the media is personal to the artist, and no two people will see or do things in the same way.

There are many, many different techniques using oil paints. Painting techniques have changed and evolved over the centuries. Below is a list of various different approaches and techniques, but it is not comprehensive by any means.

Alla Prima

Before the Impressionists in the nineteenth century paintings had been built up in layers with colour added at the final stages. Impressionists abandoned this laborious, time consuming and restricting method and painted ‘alla prima’ (Italian for ‘at first’), completing paintings rapidly, with colour going directly onto a painting, often quite thickly.

Wet into wet

If one paints ‘alla prima’ it is wet into wet. The drying times of oil paints means that you put fresh moist paint into, on top of and beside existing wet paint. The method is not quite as easy as it sounds; it is best not to overwork or you can end up with a churned up mess.  If this happens it is often best to scrape the area back with a palette knife and start again. The technique does not easily allow for precise linear detail, and possibly works best with large blocks of colour. When things do go well it can be particularly rewarding and fresh.

Underpainting

Underpainting simply means a layer of paint below the top layer.  Some artists cover their whole canvas with washes of very thin paint, either monochrome, tonal or colour washes. They allow this to dry and gradually build up to thicker paint.  This underpainting can act as scaffold on which to plan a picture and many artists leave areas of the underpainting visible in the final work. Different coloured underpainting can enhance further layers, for example green under the flesh tones of a portrait.

It is possible to do underpainting using quick drying acrylic paints, and once dry, to paint over in oils.  It is NOT possible to use acrylics on top of oils.

Underdrawing

Underdrawing is the preliminary drawing made in a single colour directly onto a support. It can be done with thin paint, or charcoal, or tracing from other preparation drawings. If you use charcoal it is advisable to fix it before painting or it will make the paint dirty.

Working on tinted ground

Up to the middle of the nineteenth century it was standard oil painting practise to work on a support that had been given an all over tint called an ‘imprimatura’. The Impressionists largely painted directly onto untinted, or white canvas. Colouring the canvas can provide a mid tone allowing you to work up to the lightest tones, and down to the darkest.  The choice of ground will influence the painting. Neutrals such as browns and greys are a good base for bright colours.  Some artists like harmonising grounds, others opt for contrast.  Small areas of ground often show through between brushstrokes.  A bit like underpainting, a ground can be laid using acrylic or thinned oil. . An underdrawing can go on top of a ground, as can any sort of underpainting.

A ground should be allowed to dry before continuing further with a painting.

Impasto

Impasto is thicker than usual paint. It can be built up to create a range of exciting surface textures.  It requires a great deal of paint so is often bulked out with special impasto mediums which are added at the colour mixing stage. It tends to be added at the final stages of a painting, and to take some time to dry. Some artists apply paint directly from tube to support and model it with a knife or fingers or brush, resembling a relief sculpture.

Glazing

Glazing is a traditional technique using oil paints very thinly, building up layers of transparent colour.  The brilliant blues and reds in the gowns of early Renaissance Madonnas were achieved using this painstaking method.  There are special glazing mediums which cut down drying times and enhance transparency. Some colours are inherently more transparent than others and possibly lend themselves to glazing more effectively.

If you wish to lay a glaze over thick paint it is important to make sure the thick paint is dry.

Removing paint

This is about wet paint and not dry paint. Assume dry oil paint will not be removed. If you wish to remove wet paint more or less completely then a rag and turpentine will do the job quite well, if a little roughly.  There are other methods that go down to layers beneath the top layer with varying effects.

  • Scraping Back. If you scrape an area with a palette knife you will find you are left with a ghost image beneath. It is similar to a layering technique. With each new application of colour, followed by scraping, beneath will reveal something of the colour remaining. If you work on a textured support such as canvas the knife removes only colour from the top of the raised grain.
  • Sgraffito. This comes from the Italian sgraffiare – to scratch, and involves scratching into wet paint using anything from the end of a paintbrush to a twig to a fingernail.  This can be a useful technique to suggest fine details.
  • Tonking.  This was used by Sir Henry Tonks, professor at the Slade School of Art. It involves placing a piece of newspaper over a wet painting and gently rubbing to transfer the paint to the paper. This can be useful for a painting where too much detail has been added too early. It can be a little haphazard.

This is a basic guide to materials and techniques, but a painting involves more than just these.  Tone, colour, composition, structure, form, rhythm and movement all come into making a picture interesting.  The better informed you are the more confidently you can approach your painting. The most important thing is to keep experimenting and practising. Some attempts will end in failure, but sometimes the failures lead to new discoveries and new forms of expression. Keep at it.

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Jackson’s Art Supplies have a very good guide too – see below

https://www.jacksonsart.com/a-guide-to-oil-painting

 

 

 

Art courses, in Hampshire and beyond

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