Glazing in Oils, by Marcel Desbiens

People often ask me what’s the difference between a photograph (or printed image) and a painting. Beside the fact that the latter is made by someone, so has an expressive aspect, there are also many visual qualities added to the optical illusion that can be produced by oil colours.

The advantage is the luminosity created by layering the paint gradually from thick and opaque to a thin sheer veil giving life to your colour. Light travels through the glaze and is reflected back off the opaque layer bellow. This of course will show best in a multi layering application of the paint like a painting from Vermeer. With the Alla Prima technique it is also possible to use a tinted background showing through the more or less opaque layer.

If you want to learn and practice with me, we run regular workshops, so put yourself on the waitlist at Glazing in Oils

If you want to read more about the way to use glazing in your painting, see the below article from Arts and Illustrators

What is a glaze?

Over the centuries, artists have used glazing as a means of creating colours that are richer than would be possible by simply mixing paint on the palette. A glaze is a thinly applied, transparent layer of colour contained within oil or acrylic glaze medium. Before application, a glaze mix will look a bit like coloured varnish. It is applied thinly with a fairly soft brush – my own preference is a long, flat, hog’s hair brush. Glazing can be applied in many separate layers, each one adding to the total cumulative effect.

A painting made with glazes is unique in the fact that each layer applied is distinctly separate from the paint below and above it. Glazing is always done on top of dry paint and, because of this, the colours of each layer do not physically mix with each other. Each layer remains pure, resulting in an interaction of bright, clear colours that can be fascinating to the eye, in which each layer contributes to the total visible effect.

The transparency in a glaze layer allows light to pass through it, reflect from the underlying paint and back out again so that when we look at a painting which has been glazed we are actually seeing an ‘optical mix’ comprised of each glaze layer, plus the painting that lies below. In addition, applying a glaze can assist in ‘bringing out’ the underlying colours within a painting, a bit like oiling wood to show the grain. By their nature, glazed colours will appear deeper and more saturated.

Top Tips

1. Always work wet on dry. Each glazed layer must be allowed to dry before you apply the next, so drying times are important. In oil painting, a fast drying, Alkyd-based medium like Winsor & Newton’s Liquin mixed with turpentine is helpful. Always try to work ‘fat over lean’ too – in other words, start painting with very little oil or medium in the mix and gradually increase the proportion of oil to turpentine as you progress throughout the painting. A ‘lean’ layer over a ‘fat’ one may not adhere properly, looks dull and might eventually crack.

2. Use glazes sparingly. A glaze can be graduated from dark to light, like a watercolour wash, by increasing or decreasing the ratio of paint to medium as you work, or by brushing more thinly. The whole painting does not have to be glazed either – you are in control of which areas receive it.

3. Work the layers before they dry. A glaze can be shaped to work in a specific area and once applied it can be manipulated in several ways before it dries. A brush carrying a small amount of glaze medium or turps can be used to remove part of the layer you’ve just painted to create highlights that can be ‘drawn’ in as required.

4. Subtract, don’t just add. A combination of brush and kitchen roll can remove even more. Simply dab with kitchen roll after diluting the glaze with the brush, as before. If you don’t like what you’ve done, gently work in some turps with a brush, dab off with kitchen roll and the glaze layer will be completely removed.

5. Try a light backdrop. Glazing works best over lighter underlying colours. It can look stunning over white or off-white highlights, giving an intensity of colour that cannot be achieved in traditional mixes. Experiment at first with a trace of a single colour mixed into your medium, paint thinly and progress from there.

Enjoy your new experiments…

Marcel Desbiens, Master Artist