Improving Your Oils

Norfolk Painting School Live is a site for painters - and by painters I absolutely mean watercolourists, acrylic, gouache, tempera and oil painters; however my experience tells me that most painters will eventually gravitate towards oils, as their needs and abilities develop.

This is not to say for a second that the other media are not rewarding or challenging - few things are technically more difficult than pure watercolour for instance; simply that oils will do everything once one knows how to use them. As one needs to do more, they enable it, and through this simple path painters such as Turner gravitated towards them.

With this in mind, I'm going to present a few article from my archive on 'improving your oils', as, like Turner, I passionately believe that, of all the media, oils can offer painters the best route to realising our creative potential and bringing our creative vision to life.

Here is part one, where I recommend the subject of skies and weather as an ideal way to mess about with many of the properties which set oils apart from other media.

Improving your Oils 1: Skies and Clouds

I started oils so I could capture the wonderful skies of my adopted county of Norfolk, so I’m particularly pleased to have this opportunity to share my passion for this subject in my first article on improving your oils.

Skies; the technical challenge.

Skies, by which I mean cloud and light effects , are varied, mutable and luminous, so to capture them in oils the first decision you need to make is whether to work in a Direct or Indirect manner.

In this context I mean wet into wet by Direct ,and wet over dry by Indirect. In Art Historical terms most Impressionist and contemporary artists worked directly, most pre-impressionists, indirectly.

As most painters get on pretty well with Direct painting, I’ll focus on Indirect working practices for this article, bearing in mind that even the most complex Indirect sky benefits from a final flourish of directly applied colour in the final pass.

Indirect Sky Painting

The great advantage of Indirect painting is that it enables you to create an illusion of luminosity, by managing the optical quality of your oil films. This makes it particularly useful for painting glowing objects such as sunsets, clouds and so forth. Unfortunately most contemporary painters haven’t received training in Indirect painting, and find it challenging to create the wonderful effects which are common in pre19th century painting.

I’ve suggested a short exercise to get you started with this, if you’ve never had that training.The key to it is to manage the opacity of your paint films whilst retaining and exploiting the luminosity of the ground.

Returning to skies then a sound Indirect sequence is:

Working on a white gesso

  1. Establish the background sky using translucent to semi opaque paint, ensuring it is workably dry

  2. Block in the clouds working from semi to fully opaque

  3. Let it dry

  4. Establish/refine any local light colour with a fairly weak glaze

  5. Revisit the clouds using translucent, semi opaque and finally, opaque paint, taking care to ensure the underpainting is still visible where appropriate.

This basic approach should serve you well for pretty much any traditional sky, although you’ll need to flex the colours, mediums and grounds to suit the job in hand. For instance a Romanticism style sky, as you might see in English painting of the Georgian period would most likely be painted upon a tinted ground (Constable typically preferred a light pink for example, but might choose buff or even a soft grey depending on the desired final effect ).


Once the sky is roughly established, it is the perfect chance to practice your glazing techniques. Being translucent films of paint, glazes work in exactly the same way (in an optical sense) as light; so by simply running a red glaze over a sky one can simulate the effect of fading, reddish twilight.

Similarly you can select good general glaze colours for various light states, dawn , dusk, night and a hot summers day, for instance, all benefit from thinking about which colour is the best choice to glaze over an underpainting.

Some tried and tested over glazing colours include:

  • Pinks for sunrise

  • Yellow to orange to red for sunsets

  • Greens or Blues for nocturnes

  • Subtle peppermint greens, cool lemon yellows or watery crimsons for winter

  • Warm blues for summer

  • Subtle greys for ‘soft’ weather

Colours, Grounds and Mediums

Skies need absolute translucency, smoky depth and strong opacity, so choose a wide range of opacities from your paint box. Most blues are translucent of course, and most whites opaque, but beyond that you should consider buff, pinks, browns and black as your ‘standards’.

Compared to the Old Masters, or even 19th Century painters, we have far more useful and luminous colours fir sky painting. Transparent Oxides are particularly useful in this respect. Compare a traditional Yellow Ochre with Transparent Earth Yellow, and you’ll see how much better our colours are are creating an effect of glowing colour.

That said and generally speaking I restrict my English skies palette to low saturation colours, as they suit the quality of light in the UK. My Dutch, northern European and American East Coast students agree and use much the same palette. My students from Africa, Oceana or SE Asia find they need to choose colours which evoke the light of their region.

Skies are optically complex, so it makes sense to keep them chromatically simple. A palette of blue, orange, black and white for instance. In the UK this might translate as:

  • Ultramarine Blue

  • Raw Umber

  • Ivory Black

  • Titanium White

Changing just one of these (Raw to Burnt Umber for instance) will have a dramatic effect on the ‘feel’ of the resulting painting, as such a limited palette draws heavily, and exploits to its fullest extent, every colour.

Even this simple arrangement offers great complexity, as each colour differs in opacity, value, hue , temperature and (despite my efforts) saturation. So for example one might mix from these:

  • Blue and orange = grey

  • More blue = cooler desaturated grey

  • More orange = warmer desaturated grey

  • More white = lighter and more opaque grey

  • More black = darker and more translucent grey

  • Blue on its own (translucent)

  • Orange on its own (semi opaque)

  • White on its own (opaque)

  • Black on its own (translucent)


My strong advice is to keep it simple. A straightforward alkyd medium such as Galkyd or Liquin, thinned when appropriate is ideal for sky painting. Using such a medium helps immensely with Indirect painting as it controls the opacity, rheology (‘feel’) and drying rate of the paints.

Once you get a feel for it try some more complex media such as megilps or waxes, these can help to create incredibly subtle and luminous effects and are common in 19th century paintings. I’ll look at some useful mediums for oils later in this series, article 3 if memory serves…


Nothing, I repeat nothing is more important in oils than the ground one paints on, get it wrong and your picture is compromised from the start. Generally speaking commercial grounds are fairly wretched if you buy budget canvases or art boards, so please get a decent support before you try sky painting.

White gesso of course offers the maximum reflectivity,and therefore the greatest potential luminosity as a base for sky painting. Coloured skies (sunsets for example), can benefit from being painted on coloured grounds, and even a soft pink is useful if you can leave enough of it extant to work with any blue overpainting. Flemish grounds (yellowish priming) are good for cooler skies, affording a greenish tinge to the work, Turners early sea paintings are often worked up on a flemish bole of sorts.

  • White is the best choice- the more reflective the better

  • Sunrise or sunset coloured grounds can be useful (red, pink, orange etc)

  • Light Pink is traditional and useful for predominantly blue skies - it offers a soft compliment to cool blue, but needs to be covered carefully to allow it to do this job.

  • Soft buff or yellow can be useful for cool ‘Dutch’ skies

  • For a subtle sky use a solid ground colour

  • For a livelier sky use an imprimatura


Skies are mutable, so it’s best to initially suggest their broad expanse by blocking them in with good sized brushes, rather than fussing over them with a 00 Sable. I recommend that you block in with a decent sized varnish brush, before systematically moving down to the larger sizes of filberts or rounds, and finishing off with a touch or two from a bright - or square- brush for any high impasto.

Beware of using too much palette knife in traditional skies - you’ll need it , but not to the extent that most contemporary painters use the tool.

Reserve it for the brightest and final touches - Constable’s oil sketches and small oils are exemplary. Turner’s move from using mostly brushes, to rags and knives for his later paintings is a good example of the difference that may be had from emphasising knife over brush; compare his work with more traditional skies and see what you prefer.

  • Choose larger brushes

  • Move from large to small

  • Reserve the knife for agents

  • If you like later works by Turner use mostly rags and knives after the first block in.

Key Points

  • Work translucent to opaque

  • Work big to small

  • Keep your palette simple

  • Exploit the ground colour

  • Be conservative with impasto

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