Glue and gesso are used to protect the canvas—or other surfaces— from the oil paint. The Imprimatura, or ‘first paint layer’, is a colour painted over the underground. John Constable described his prepared canvases as ‘flats’. I use acrylic a lot of the time for the underground because readymade canvases already have a white coat of acrylic. Only for commissions do I make my own background, and then make an oil paint imprimatura.
Always look at the edges of a painting, or where the paint is very thin, to see the colour of the underground imprimatura. The imprimatura is the first big decision you make in your painting—it is now often overlooked as people paint on a white canvas because that is how they bought it. This makes it easy to spot amateurs.
There are many colours that are traditionally used for underpainting: burnt or raw umber, burnt sienna, or ultramarine blue. Almost any pigment can be used as long as it is capable of producing an adequate value range from light to dark. Yellow or medium-toned pigments, for example, cannot do this.
The broader question, however, is whether the underpainting colour should be similar to the dominant colour of the subject, or in contrast to it?
One rule is to use a warm ground for a painting dominated by cool hues, and a cool ground for a painting dominated by warm hues. Another is to use a complementary colour to the dominant colour in the composition. For example green for portraits (complementary to red, a colour used in mixing skin tones). One tip with oil paints is to wipe off the underground for highlights, allowing the white underneath the coloured layer to show through more.
1. Yellow Ocher/Raw Sienna
These earth yellows provide a rich, warm imprimatura which maintains a sense of luminosity. Used by landscape and portrait painters to give a work a warm, golden undertone. You can see this used in works by Rubens and Rembrandt.
A light-toned grey is a multi-purpose imprimatura and is useful for all genres. It also allows flexibility for when your colour scheme is still undecided. It was sometimes used by artists such as Monet and Vermeer.
Light grey imprimatura:
Johannes Vermeer 1632-1675, the Milkmaid
Light coloured imprimatura, off white or pale grey, but for only the head he put a rough patch of white;
Joshua Reynolds 1723- 1792; Mrs. Hartley as a Nymph with a Young Bacchus.
3. Earth Green
Earth Green was often used under areas of flesh by Byzantine and Medieval painters, such as Duccio, of the 13th and 14th centuries, but continued to be used after Michelangelo. The green helps neutralize the effects of strong pinks and reds, allowing for natural skin colour.
Green under the faces imprimatura;
Michelangelo 1475-1564, The Virgin and Child with Saint John and Angels.
4. Earth Red/Burnt Sienna
Used by landscape artists to give space to green foliage, it also creates a mauve hue when sky and clouds are painted over it. This effect can be seen in works by Turner. These colours are also used by figure and portrait painters to help establish warm shadow masses and were often used in the French figurative tradition by artists ranging from Poussin to Degas.
Jean-Auguste-Dominique Ingres 1780- 1867, Oedipus and the Sphinx
5. Light brown
Constable and Thomas Gainsborough.
Light brown imprimatura;
Thomas Gainsborough 1727- 1788, Mr. and Mrs. Andrew
6. Dark Brown or ‘bole’
A bole ground is usually an opaque mixture of Earth or Mars Red, Black, and a small amount of Yellow Ochre. Still used today by traditional portrait and figure painters, a bole background came into style with artists such as Caravaggio and the young Velazquez.
7. Burnt Umber/Raw Umber
Both are cheap, quick drying, and semi-transparent, making them ideal for a thin imprimatura. These colours were used by artists such as da Vinci and Van Eyck.
8. Light Blue
Sometimes preferred by alla prima painters as a luminous base, using a blue imprimatura allows for water, skies, and atmospheric effects to be developed quickly.9.White
A plain white imprimatura is the most luminous imprimatura for glazing. The drawback is that it makes opaque paint appear darker by contrast. The white ground was first consistently used by Manet, and then later by artists such as Seurat, Derain and Pre-Raphaelites. But most impressionists used an off white ground.
Whistler often used a dark ground, even black.
11. Mixed Colours
El Greco was supposed to have ‘scraped up the remaining wet colours on his palettes and used the resulting brown mixture of his grounds’.
Red ochre and gesso, outlines of composition are sketched with black, possible charcoal with oil, light areas were blocked in with white or pale grey imprimatura.
El Greco 1541 – 1614, Scourging the Moneychangers from the Temple
Use a palette the same colour as your imprimatura, so that what you mix on your palette is the same as on your canvas. Use a glass plate and put the same coloured sheet under it.
Colour also the sides of your canvas, easy for framing and you don’t have a disturbed white on the side of your painting. Make extra paint, so you can always add the colour from your imprimatura back to your painting. Keep it in a closed pot.
My painting, Thuy in Blue, with blue imprimatura
My painting, Chinese Head Dress, with orange imprimatura