The traditional and most common support—material to which the paint is applied—for watercolor paintings is paper. Other supports include papyrus, bark papers, plastics, vellum, leather, fabric, wood and canvas. Watercolor paper is often made entirely or partially with cotton, which gives a good texture and minimizes distortion when wet. Watercolors are usually translucent, and appear luminous because the pigments are laid down in a pure form with few fillers obscuring the pigment colors. Watercolors can also be made opaque by adding Chinese white.
In East Asia, watercolor painting with inks is referred to as brush painting or scroll painting. In Chinese, Korean and Japanese painting it has been the dominant medium, often in monochrome black or browns. India, Ethiopia and other countries have long watercolor painting traditions as well.
Watercolor painting is extremely old, dating perhaps to the cave paintings of paleolithic Europe, and has been used for manuscript illustration since at least Egyptian times but especially in the European Middle Ages. However, its continuous history as an art medium begins with the Renaissance. The German Northern Renaissance artist Albrecht Dürer (1471–1528), who painted several fine botanical, wildlife, and landscape watercolors, is generally considered among the earliest exponents of watercolor. An important school of watercolor painting in Germany was led by Hans Bol (1534–1593) as part of the Dürer Renaissance.
Despite this early start, watercolors were generally used by Baroque easel painters only for sketches, copies or cartoons (full-scale design drawings). Notable early practitioners of watercolor painting were Van Dyck (during his stay in England), Claude Lorrain, Giovanni Benedetto Castiglione, and many Dutch and Flemish artists. However, botanical illustration and wildlife illustration perhaps form the oldest and most important traditions in watercolor painting. Botanical illustrations became popular during the Renaissance, both as hand-tinted woodblock illustrations in books or broadsheets and as tinted ink drawings on vellum or paper. Botanical artists have traditionally been some of the most exacting and accomplished watercolor painters, and even today, watercolors—with their unique ability to summarize, clarify, and idealize in full color—are used to illustrate scientific and museum publications. Wildlife illustration reached its peak in the 19th century with artists such as John James Audubon, and today many naturalist field guides are still illustrated with watercolor paintings.
Several factors contributed to the spread of watercolor painting during the 18th century, particularly in England. Among the elite and aristocratic classes, watercolor painting was one of the incidental adornments of a good education; mapmakers, military officers, and engineers used it for its usefulness in depicting properties, terrain, fortifications, field geology, and for illustrating public works or commissioned projects. Watercolor artists were commonly brought with the geological or archaeological expeditions, funded by the Society of Dilettanti (founded in 1733), to document discoveries in the Mediterranean, Asia, and the New World. These expeditions stimulated the demand for topographical painters, who churned out memento paintings of famous sites (and sights) along the Grand Tour to Italy that was undertaken by every fashionable young man of the time.
In the late 18th century, the English cleric William Gilpin wrote a series of hugely popular books describing his picturesque journeys throughout rural England, and illustrated them with self-made sentimentalized monochrome watercolors of river valleys, ancient castles, and abandoned churches. This example popularized watercolors as a form of personal tourist journal. The confluence of these cultural, engineering, scientific, tourist, and amateur interests culminated in the celebration and promotion of watercolor as a distinctly English "national art". William Blake published several books of hand-tinted engraved poetry, provided illustrations to Dante's Inferno, and he also experimented with large monotype works in watercolor. Among the many other significant watercolorists of this period were Thomas Gainsborough, John Robert Cozens, Francis Towne, Michael Angelo Rooker, William Pars, Thomas Hearne, and John Warwick Smith.
From the late 18th century through the 19th century, the market for printed books and domestic art contributed substantially to the growth of the medium. Watercolors were used as the basic document from which collectible landscape or tourist engravings were developed, and hand-painted watercolor originals or copies of famous paintings contributed to many upper class art portfolios. Satirical broadsides by Thomas Rowlandson, many published by Rudolph Ackermann, were also extremely popular.