the texture of easel paintings from the view of art-conservation techniques

texture, one of the important elements in visual arts, is produced in different ways. whereas each painting is a multilayered object, any separate layer can have its own distinct texture. texture can be resulted of inherent nature of artist's depicted materials, such as canvas or support, and it can be, also, produced in the ground or paint layers. in addition, by using of different materials, the artist can make his ideal texture. it is remarkable that some cracks appear on the painting layers throughout the time which make a unique – homogenous texture. such a texture, demonstrates the antique validity of the painting. considering the importance of texture and its way of development, therefore, the texture protection should be seen as a basic tenet of art conservation and restoration knowledge. obviously the protection and transmission of innate meanings of any art objects seriously is dependent on the protection of whole material construction. any variation in texture equals to alteration in meanings and serious deterioration of painting's integrity. by the way, it is usual to see the simultaneous texture alteration and material construction. being one of the 20th century artist’s main tasks, making of texture has been developed in different ways. in second half of the last century, when the ready-made materials such as wall paper and fabric became popular and unlimited, expansion of materials variety took place, this visual element gained a new worthy importance. the paper considers the support layer, ground layer, pain layer texture and texture imposed to the object by surface cracks. moreover, the techniques and methods to make such effects are considered by the authors. it is notable that applying of canvas texture on the support layer and to make a texture by artist discussed in art since the 20th century onward. for instance impressionists use such a technique to make a thick layer of color. however, it is possible for a soft surface to turn to a coarse one by new cracks throughout the time. artists have used canvas and wood as support for easel painting. different methods of ground layer preparation, made the artists to produce different textures on ground layer. pastiglia and gilding resulted in a shining surface in italian paintings before 1400 ad. in the early 20th century the artists applied absorbent grounds which could produce a fresco surface. in 1920s, materials other than paints were added to painting, to artists with making new textures. cubist artists applied these materials for the first time in collage technique including wallpaper pieces, fabric, and newspaper and so on. to produce a texture, later, artists applied more materials such as sand, plaster, and so on. in this paper, after classifying different kinds of texture and reviewing the history of easel painting texture and its techniques, the effect of time on different painting layers is discussed. having a new valuable approach to materials and techniques of some well-known contemporary artists in different periods of time is the main highlight of this essay.