Art

Acrylic painting

Acrylic artist paints may be thinned with water and used as washes in the manner of watercolor paints, but the washes are not re-hydratable once dry. For this reason, acrylics do not lend themselves to color lifting techniques as do gum arabic based watercolor paints.

Fluorescent acrylic paints lit by UV light. Paintings by Beo Beyond
Acrylic paints with gloss or matte finishes are available, although a satin (semi-matte) sheen is most common; some brands exhibit a range of finish (e.g., heavy-body paints from Golden, Liquitex, Winsor & Newton and Daler-Rowney).Politec acrylics are fully matte. As with oils, pigment amounts, and particle size or shape can naturally affect the paint sheen. Matting agents can also be added during manufacture to dull the finish. The artist can mix media with their paints and use topcoats or varnishes to alter or unify sheen if desired.

When dry, acrylic paint is generally non-removable from a solid surface. Water or mild solvents do not re-solubilize it, although isopropyl alcohol can lift some fresh paint films off. Toluene and acetone can remove paint films, but they do not lift paint stains very well and are not selective. The use of a solvent to remove paint will result in removal of all of the paint layers, acrylic gesso, etc. Oils can remove acrylic paint from skin.

Only a proper, artist-grade acrylic gesso should be used to prime canvas in preparation for painting with acrylic. (However, acrylic paint can be applied to raw canvas if so desired without any negative effect or chemical reaction as would be the case with oils)) It is important to avoid adding non-stable or non-archival elements to the gesso upon application. However, the viscosity of acrylic can successfully be reduced by using suitable extenders that maintain the integrity of the paint film. There are retarders to slow drying and extend workability time and flow releases to increase color-blending ability.
Source: Wikipedia

Oil paintings

Traditional oil painting techniques often begin with the artist sketching the subject onto the canvas with charcoal or thinned paint. Oil paint is usually mixed with linseed oil, artist grade mineral spirits or other solvents to create a thinner, faster or slower drying paint. Because these solvents thin the oil in the paint, they can also be used to clean paint brushes. A basic rule of oil paint application is ‚fat over lean‘. This means that each additional layer of paint should contain more oil than the layer below to allow proper drying. If each additional layer contains less oil, the final painting will crack and peel. There are many other media that can be used in oil painting, including cold wax, resins, and varnishes. These additional media can aid the painter in adjusting the translucency of the paint, the sheen of the paint, the density or ‚body‘ of the paint, and the ability of the paint to hold or conceal the brushstroke. These variables are closely related to the expressive capacity of oil paint.

Traditionally, paint was transferred to the painting surface using paint brushes, but there are other methods, including using palette knives and rags. Oil paint remains wet longer than many other types of artists‘ materials, enabling the artist to change the color, texture or form of the figure. At times, the painter might even remove an entire layer of paint and begin anew. This can be done with a rag and some turpentine for a certain time while the paint is wet, but after a while, the hardened layer must be scraped. Oil paint dries by oxidation, not evaporation, and is usually dry to the touch within a span of two weeks. It is generally dry enough to be varnished in six months to a year. Art conservators do not consider an oil painting completely dry until it is 60 to 80 years old.
Source: Wikipedia

Sculptures

Worldwide, sculptors have usually been tradesmen whose work is unsigned. But in the Classical world, many Ancient Greek sculptors such as Phidias began to receive individual recognition in Periclean Athens. In the Middle Ages artists such as the 12th century Gislebertus sometimes signed their work, and were sought after by different cities, especially from the Trecento onwards in Italy, with figures such as Arnolfo di Cambio, and Nicola Pisano and his son Giovanni. Many sculptors also practised in other arts; Andrea del Verrocchio also painted, and Giovanni Pisano, Michelangelo, and Jacopo Sansovino were architects. Some sculptors maintained large workshops.

From the High Renaissance artists such as Michelangelo, Leone Leoni and Giambologna could become wealthy, and ennobled, and enter the circle of princes. Much decorative sculpture on buildings remained a trade, but sculptors producing individual pieces were recognised on a level with painters. From the 18th century or earlier sculpture also attracted middle-class students, although it was slower to do so than painting. Women sculptors took longer to appear than women painters, and were less prominent until the 20th century.
Source: Wikipedia