As a basis for painting, the use of canvas has been known since ancient times. For example, Pliny testifies that the portrait of Nero, painted by one of the artists of that time (I century AD) by order of Nero himself, was executed on canvas, and not on wood, as was customary at that time, and the length of this painting was 40 m. One of the Fayum portraits of the end of the IV century is also painted on the canvas . A dense, not particularly fine woven canvas was chosen as the base.
Canvas was widely used in oil painting in Italy in the late XV – early XVI century . For the first time, Florentine and Venetian painters began to use canvas quite actively, and after them the artists of the northern schools – the Dutch and Germans, in the XVIII century and in Russia the first secular easel paintings made on canvas appeared.
Most of the canvases of Italian, Spanish and German painters of the XV–XVI centuries. in their texture are a rather complex weave of twisted hemp or linen threads, made by hand (Fig. b). Many painters of the late XVI century used exclusively twill fabric as a painting canvas. Tintoretto, Titian, Veronese, many Flemish and Dutch painters painted exclusively on twill canvases. This is due to the fact that due to the twill nature of the interweaving of the threads, the adhesion between the soil particles and the surface of the twill canvas is much greater than in the usual one. In addition, all physical and mechanical external influences have a lesser effect on the soil lying on the twill canvas than on the soil lying on a plain canvas (Fig. a).
The word "canvas" does not mean any particular fabric.
This is a common name accepted in the artistic environment for the fabric material used for the pictorial base. Canvases differ in elasticity, strength and the ability to maintain their original state with changes in temperature and humidity. The strength of the canvas is due to the nature of the source material, the quality, length and strength of individual fibers, as well as the spinning of the thread, the norm and uniformity of twisting. The quality of canvases depends on the fabric structure, dressing, weight and density. The structure implies the quality and quantity of fibers. Weaving determines the weave (texture). The weight of the canvas is calculated in grams per square meter (before priming), the density of the number of warp threads and weft - per square centimeter.
Fabric as a basis for painting has great advantages over other materials, but it has its drawbacks. Paintings painted on canvas are light, they can be removed from stretchers, rolled into rolls, carried and transported, which is very convenient, especially when organizing traveling exhibitions. The disadvantage of the canvas is weak resistance to external mechanical influences: it is easy to push, pierce, cut. In addition, the canvas reacts noticeably to changes in temperature and humidity, since its expansion coefficient is very large.
In painting, various fabrics are used as a basis. They are produced from yarn obtained from vegetable, synthetic and combined fibers. However, not all of them are suitable as a picturesque base. Let's consider the technical data of non-primed fabrics most often used by artists.
Linen canvas is made of yarn, the fiber of which is obtained from flax stalks. It has a grayish and yellowish color. It has the greatest strength and resistance to the influence of atmospheric moisture, temperature fluctuations. Flax fiber is incomparably less capable than others of structural changes caused by external physical and mechanical influences. This allows linen fabrics to retain their original texture (grain), which is of no small importance for painting. Linen canvases, depending on the quality of the threads and dressing, can be divided into yarns made of long fiber, and from the waste of the primary processing of yarn - ochesa and short fiber. The fabric made of linen yarn of long fiber has a more even thread in thickness, it is better than that of short fiber and ochesa, which is very uneven (knots, thickening, thinning), contains remnants of plant epidermis (bonfires).
The severe canvas (sideboard) and theatrical are made of ochesa and short fiber, are produced for domestic and technical use. They are fragile, easily deformed. In addition, the canvas is harsh in the production process is treated with acid, therefore it has an increased acidity, which negatively affects its strength. Uneven threads require special stripping after sizing, this violates the strength of the canvas, leads to uneven stress of the sizing base and the soil. It is in the stressed areas on the sizing and the ground that cracks occur earlier than in the rest of the plane. Thus, the soil freely passes the paint binder to the back of the canvas. According to the results of monitoring the safety of the paintings on these canvases, it is obvious that they are unsuitable for painting. Unfortunately, many of the works of our artists are written and are being painted on such canvases. Also unsuitable is burlap made of coarse-stemmed (hard, bast) fibers: jute, kenaf and waste from primary processing and carding of low-dimensional flax and short fiber.
Hemp canvas is made of yarn, the fiber of which is obtained from hemp stalks. It has a gray-white and greenish tint. The worst grade is yarn made of fibers, slightly yellow or brown in color. The strength of the yarn is equal to linen. Currently, hemp canvases for painting are not produced. They are used only for technical needs.
Jute canvas is made from yarn obtained from the stems of jute. It has a strong luster, light yellow color. Jute yarn is fragile. Its strength is incomparably lower than that of flax and hemp yarn. It is not recommended for scenic purposes.
Cotton canvas is made from yarn obtained from cotton seeds. It has a creamy white color. In terms of strength, it is significantly inferior to linen fabrics. It is very hygroscopic (absorbs moisture), prone to rotting, mold easily develops in it. Stretched on a stretcher, the cotton canvas sags after a while. It is not recommended for scenic purposes.
Synthetic canvas is produced from yarn, the thread of which is obtained from polyester (it is produced from waste oil storage). It is durable, very resistant, not subject to rot, has no tendency to expand and contract depending on the humidity of the environment. Nevertheless, the issue of using polyester canvases as a basis for painting cannot be considered definitively resolved. This canvas has not passed the test of time.
Combined canvas is the most common in the art materials market. It is produced from threads combining plant and chemical fibers. Domestic production produces so-called semi-linen canvases consisting of flax fibers and synthetic yarns. Such canvases are distinguished by a lighter tone, since synthetic warp threads (made of polyester or dacron) are white, shiny, and linen weft threads are gray. Imported canvases (most of them) are produced in a combination of linen with cotton, with polyester, with polyester and viscose, cotton with polyester and viscose, or only with polyester. Combined canvases have different elasticity and stability. Each type of fiber absorbs moisture differently, while changing the degree of tension of the entire surface of the canvas on the stretcher. Unequal hygroscopicity of raw materials, and consequently, unequal adhesion to the soil, causes rapid destruction of the paint layer. Therefore, it is possible to raise the question of the rationality of using combined canvases as a basis for painting.
Interweaving of threads in fabric
The fabric is woven from yarn by two mutually perpendicular systems - warp and weft (warp threads go along the length of the fabric, weft threads - across). According to the method of grouping overlapping threads, the main types of weaving weaves are distinguished: linen, twill, satin; other more complex weaves are formed by combining the main ones. The linen (headset) weave is a sequentially alternating main and weft threads. In weaving, linen weaving is called linen, cotton weaving is called mitkalev. With twill and satin weave, the weft thread passes not under one warp thread, but under several. Thus, diagonal lines of twill (hem) are formed on the fabric. With satin laying, a fabric is obtained on which, on one side, the threads of either the warp (satin) or the weft (satin) predominate. The fabric bases for painting mainly use linen and twill (currently not available) weave. Other weaves - knitted, braided, lace, tulle - are unsuitable for pictorial purposes.
The texture (grain) of the canvas is one of the main components of the construction of the picturesque and colorful layer of the work. It is determined by the thickness of the fabric threads and is divided into fine-grained, medium-grained and coarse-grained. The texture of the non-primed canvas is the same on both sides.
According to the method of weaving, canvases are made with two threads on the base and one thread on the weft (theatrical canvas), others with one, two, three or four threads in both directions.
Basic requirements for canvases
Canvases for painting should be unbleached, dense, with even weaving, with threads of uniform thickness (warp and weft), without knots and other irregularities on the surface of the fabric (breaks, sticking threads of the remains of the bonfire). They must have great strength and special resistance to various effects of atmospheric moisture and temperature fluctuations. Bleaching is used during the production of canvas to remove impurities and unwanted coloring, to give white color and prepare for dyeing. The most widely used solutions of acids and alkalis, oxidizers and reducing agents, which negatively affects the strength of the canvas for painting.
Dense fabrics with frequent interweaving of threads are less susceptible to moisture, and the safety of the executed colorful layer is incomparably higher than on fabrics with rare interweaving. The twill weave canvas is denser, less destroyed by changes in temperature and humidity conditions, since when swelling, the friction between the twill weave threads is less than that of plain. The use of rare, loose canvases usually leads to the appearance of strong mechanical stress in the tissues, causing significant changes in volume (greater shrinkage) and leading quite soon to cracking, and often shedding of the paint layer. With uneven thread thickness, the reaction to temperature and humidity is different in different places. Unevenness causes a violation of the connection of the canvas with the ground and premature aging of the work. In addition, difficulties arise when gluing and priming the canvas. The adhesive film lies unevenly (sometimes falling through), and the soil applied to it forms an uneven coating. These shortcomings are usually found when writing: the tone "fails" due to the fading of the paint layer in certain areas (while the initial tone changes dramatically). The presence of weaving defects in the canvases has an extremely unfavorable effect on the visual perception of the picture, especially with thin-layer writing.
Harsh canvases produced by our textile factories are subjected to special processing, consisting of the following operations: preliminary steaming of yarn and its dressing; acidification of canvas, its dressing and calendering.
Yarn steaming is an operation by which the salts, sugars and nitric acid substances contained in it are removed from the yarn.
Dressing is an operation in which the yarn threads used for the fabric base are wetted with boiled starch – this is done to give greater strength to the fabric.
Acidification involves treating the canvas with sulfuric acid to remove various impurities. It can be harmful if the fabric is poorly washed with water after acidification, in which case traces of acid will negatively affect the strength of the canvas and the soil applied to it.
Dressing – this operation improves the appearance of the fabric by applying starch, soap, paraffin to it. At the same time, the canvas becomes heavier, overloaded with unnecessary and superfluous materials. Calendering is the passing of canvas through the rollers of a special machine for ironing fabric, in which thickening of threads, knots and other irregularities are flattened. Although this operation is harmless, it does not justify itself, since when applying the soil, these irregularities swell and reappear, which makes it difficult to remove nodes in a timely manner and properly clean up.
To completely remove soluble salts and sugar, the canvas can be rinsed in hot water before priming. In addition, such washing contributes to a certain reduction in the "movement" of the canvas with changes in air humidity.
Painters in most cases choose a canvas by its appearance, without taking into account its properties and features, and for painting it is important to check whether there are any weaving defects on it that adversely affect the sizing and priming of the canvas and interfere with the normal conduct of the painting process, as well as the final result. It is also necessary to take into account the painting tasks, the size of the painting and the manner of writing. Fine-grained or medium-grained canvas is best suited for smooth thin-layer painting (depending on the size). Textured, pasty painting should have a thicker and stronger base.
The discrepancy between the manner of writing and the foundation leads to premature aging of the work. For example, a painting painted pastily with a large layering of paints on a fine-grained canvas, even of a small size, will not be able to contain the load and will deform according to the texture of the strokes. A large-sized painting, made with much less pasty and also on a fine-grained canvas, sags under the weight of paints.
Smooth writing on coarse-grained canvas requires excessive layering of the soil, which is unacceptable.
On a medium-grained canvas of plain weave, the sound of colors will be different than on the same canvas of twill weave. In particular, this has a strong effect on thin-layer painting. It is better not to use canvases with rare and coarse weave for a picturesque base, since rare weaving creates an insufficiently strong basis for a colorful layer (a fine net of craquelure forms along the threads of the canvas), and coarse canvas often causes the paintings to deteriorate.
A properly chosen canvas largely affects the quality of painting, the freedom and ease of conducting the painting process, affects the safety of the canvas and the work as a whole. And the skillful use of a variety of textures opens up inexhaustible possibilities for the artist to use them for the purposes of a certain factual construction of painting.