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For a textured finish, lay and then press a piece of textured material, such as an old piece of sacking, into the final primer coat.
SEE ALSO
| MAKING PRIMERS | Ready-made primers are adequate for general needs, but obviously they cannot be tailored to individual requirements. Making your own primer is economical and will give you greater control over its quality and absorbency |
Egg-oil emulsion
This general-purpose, easily made primer is suitable for canvas and board. It is ready to paint on after two days’ drying (see list of ingredients here).
Break the egg into a jar. Using the eggshell as a measure, add the same volume of refined linseed oil and twice the volume of cold water. Screw the lid on the jar and shake vigorously until an emulsion is formed. Grind a little emulsion with titanium white pigment until it forms a stiff white paste; add the rest of the emulsion to bring the mixture to the consistency of double cream. Thin the mixture to a milky consistency with lukewarm glue size mixed 1 part to 12 parts cold water. Brush very thinly onto a sized support.
Traditional gesso
Brilliant white gesso (see ingredients here), is very smooth and porous, and is the ideal base for painting luminous colours and detail. Gesso is best applied to a rigid support prepared with glue size – it is not flexible enough for use on canvas. It is most suited to water-based paints, such as tempera, acrylics and Chroma colours.
Heat the size, mixed 1 part to 8 parts cold water, gently in a double boiler. Slowly add some warm size to the whiting and stir until it forms a thick paste. Blend without creating excess bubbles. Gradually add the rest of the size until a smooth, creamy mixture is obtained. (Keep the pot of gesso warm and covered, otherwise it will harden, the water will evaporate and the glue will become too strong.) To increase the brilliance, add powdered white pigment. Leave for a few minutes before using.
Applying gesso
Apply gesso carefully in thin layers and work quickly: if you go back over an area, streaks will develop. Dampen the brush with some water to prevent air bubbles forming on the surface. Apply the first coat of hot gesso in short, even strokes (1), keeping the working edge moving – when the gesso begins to cool, move on to an adjacent area. Apply up to six coats for a dense, white finish; add each coat at right angles to the last (2), using short back-and-forth strokes. Each coat should be completely dry before the next one is applied. Level off in one direction (3). Lightly sand between coats with fine sandpaper (4), dusting off the surface before applying the next coat.
Egg-oil ingredients
• titanium white pigment
• one egg
• linseed oil
• glue size
• water
(1) Applying the first coat
(2) Adding coats at right angles
(3) Levelling off
(4) Sanding between coats
Gesso ingredients
• 1 part Gilder’s whiting
• 1 part glue size
Sealing gesso
On an absorbent gesso surface, oil paint takes on a matt, airy quality which is pleasing but makes the paint quite difficult to handle. In addition, gesso soaks up much of the oil from subsequent paint layers, leaving them brittle and prone to cracking. To overcome this, the dry gesso surface should be partially sealed with a weak solution of glue size (about half the strength used to make the gesso).
SEE ALSO
| TONED GROUNDS | Some artists like to paint on a toned or coloured ground, as a white ground can be inhibiting; by covering the canvas or paper with a wash of neutral colour, you immediately create a more sympathetic surface on which to work. |
‘Reading’ tones and colours
A white ground can give a false ‘reading’ of tones and colours, especially in the early stages of a painting, when there is nothing to relate them to. Most colours appear darker on a white surface than when they are surrounded by other colours, and this creates a tendency to paint in too light a key. If you work on a neutral, mid-toned ground you will find it much easier to assess colours and tones correctly, and you can paint towards light or dark with equal ease.
If the colour
