An artist's materials: why linen and not cotton
Table of contents
Materials are rarely discussed at purchase — they seem a technical detail that changes nothing. In fact they determine whether the work will look the same in fifty years.
Here is what a painting is made of.
The canvas
The support everything rests on. Two main options, and the difference between them is substantial.
Linen. The classic, in use since the sixteenth century. The fibre is strong, long, with natural irregularity. Its chief virtue is stability: linen barely responds to changes in humidity, so the tension holds for decades.
Another, less obvious property: linen grows stronger with time. The fibre compacts, and an eighteenth-century canvas is often in better condition than a twentieth-century cotton one.
Cotton. Cheaper, more even in texture, easier to work. But it responds strongly to humidity: it sags when humidity rises and tightens again when it falls. The paint layer does not follow that movement, and cracks appear within decades.
For studies and practice work cotton is fine. For a work bought to last decades, it is not.
Jute and hemp. Less common. Very coarse texture, suited to large works with dense paint.
Canvas weight is measured in grams per square metre. For oil painting the working range is 280–400 g/m². Lighter sags; heavier becomes stiff and heavy.
The stretcher
The wooden frame the canvas is stretched over. It looks like a simple part, but it determines whether the work holds its geometry.
Material. Pine is the standard. It must be dry, without knots at the joints. Damp wood warps the whole structure as it dries.
Keys. An obligatory part of a good stretcher. Eight wooden keys in the corners allow the tension to be taken up years later, when the canvas slackens. A stretcher without keys is a sign of cheap manufacture.
Bevelled inner edge. The inner edge must be chamfered so that the canvas does not touch it. Otherwise the imprint of the frame will show through on the front after some years.
Cross-brace. From 100 cm upward a cross member is needed, or the stretcher bows under the tension of the canvas.
The ground
The layer between canvas and paint. It does three things: isolates the fabric from the oil, gives the paint something to grip, and sets the tone.
Acrylic. The current standard. Dries fast, stays elastic, does not yellow. Ready-primed canvas is sold with it.
Emulsion ground. A mix of glue and oil. The classical option, giving a livelier surface, but it takes time to prepare.
Chalk and glue. The oldest type, used for work on panel. Very rigid; on canvas it cracks.
Number of layers: two or three, with sanding between. A single layer lets oil into the fabric, and after decades the canvas turns brittle.
Paints
Here the difference in price is greatest, and it is justified.
Pigment. The basis of the paint. Mineral pigments — cadmium, cobalt, ochre, umber — are chemically stable and do not change colour over centuries. Organic and synthetic ones can be fugitive: some fade in light within decades.
Lightfastness is marked on the tube with stars or letters. Three stars or AA is the top class, appropriate for work meant to last.
Binder. Linseed oil is the standard. It forms a strong, elastic film. Safflower and poppy oils are paler and yellow less, but the film is softer — they are used for whites and light tones.
Fillers. Cheap paints are extended with chalk and barytes: less pigment, poorer coverage, more colour shift as they dry. It shows immediately — such paint “disappears” on drying.
The price gap between student and professional ranges is threefold or fourfold. But student paint on a work bought to last decades is economy in the wrong place.
Solvents and mediums
Turpentine. The classic natural thinner. Sharp smell, requires ventilation.
Odourless mineral spirit. The modern alternative, milder.
Mediums. Mixtures of oil, resin and solvent that alter the paint's behaviour: speeding drying, making the layer more transparent, raising the gloss. Used for glazing.
The rule of “fat over lean”: each successive layer must contain more oil than the one beneath. Breaking this rule is the commonest cause of cracking in painting.
What the buyer can see of this
Practically nothing. Materials are not visible in a finished work — they reveal themselves after decades.
But some things can be checked.
The reverse. The type of canvas is visible: linen has a natural irregularity and a yellowish cast, cotton is more even and whiter.
The stretcher. Whether there are keys in the corners and a cross-brace on large formats.
Ask. The simplest method. A painter working with good materials will answer at once and gladly. Evasion is a signal.
Frequently asked questions
Does the canvas affect the price of a work?
Directly, hardly: the material difference is a few percent of the value of a medium-format work. Indirectly, yes: a painter who economises on canvas usually economises on paint too.
Which is better, canvas or panel?
Different jobs. Panel is more stable and more durable but heavy and limited in size. Canvas is lighter and allows large formats. For contemporary painting canvas is the standard.
Can paint quality be judged by eye?
Partly. Cheap paint gives a dull, as if dusty colour and mattes down considerably as it dries. Professional paint holds its saturation. But it is reliably visible only when two works are compared side by side.
What materials do you work with?
Linen from 320 g/m² on a pine stretcher with keys, acrylic ground in two or three layers, professional oil paints with mineral pigments. That is not a marketing formula but the minimum at which a work survives a century.
The materials of each work are recorded on the certificate of authenticity. If you would like technical details of a particular canvas, write to me.
