Joined: Mar 16, 2009
Tue Mar 17, 2009 12:09 am
A watercolor is the medium or the resulting artwork, in which the paints are made of pigments suspended in a water soluble vehicle. The traditional and most common support for watercolor paintings is paper; other supports include papyrus, bark papers, plastics, vellum or leather, fabric, wood, and canvas. 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 also have long traditions. Fingerpainting with watercolor paints originated in China.
Watercolor paint consists of four principal ingredients:
colorant, commonly pigment (an insoluble inorganic compound or metal oxide crystal, or an organic dye fused to an insoluble metal oxide crystal);
binder, the substance that holds the pigment in suspension and fixes the pigment to the painting surface;
additives, substances that alter the viscosity, hiding, durability or color of the pigment and vehicle mixture; and
solvent, the substance used to thin or dilute the paint for application and that evaporates when the paint hardens or dries.
The term "watermedia" refers to any painting medium that uses water as a solvent and that can be applied with a brush, pen or sprayer; this includes most inks, watercolors, temperas, gouaches and modern acrylic paints. The term watercolor refers to paints that use water soluble, complex carbohydrates as a binder. Originally (16th to 18th centuries) watercolor binders were sugars and/or hide glues, but since the 19th century the preferred binder is natural gum arabic, with glycerin and/or honey as additives to improve plasticity and dissolvability of the binder, and with other chemicals added to improve product shelf life. Bodycolor is a watercolor made as opaque as possible by a heavy pigment concentration, and gouache is a watercolor made opaque by the addition of a colorless opacifier (such as chalk or zinc oxide). Modern acrylic paints are based on a completely different chemistry that uses water soluble acrylic resin as a binder.
Watercolor painters before c.1800 had to make paints themselves using pigments purchased from an apothecary or specialized "colourman"; the earliest commercial paints were small, resinous blocks that had to be wetted and laboriously "rubbed out" in water. Modern commercial watercolor paints are available in two forms: tubes or pans. The majority of paints sold are in collapsible metal tubes in standard sizes (typically 7.5, 15 or 37 ml.), and are formulated to a consistency similar to toothpaste. Pan paints (actually, small dried cakes or bars of paint in an open plastic container) are usually sold in two sizes, full pans (approximately 3 cc of paint) and half pans (favored for compact paint boxes). Pans are historically older but commonly perceived as less convenient; they are most often used in portable metal paint boxes, also introduced in the mid 19th century, and are preferred by landscape or naturalist painters. Among the most widely used brands of commercial watercolors today are Daniel Smith, Daler Rowney, DaVinci, Holbein, Maimeri, M. Graham, Schmincke, Talens (Rembrandt), and Winsor & Newton.
Thanks to modern industrial organic chemistry, the variety, saturation (brilliance) and permanence of artists' colors available today is greater than ever before. However, the art materials industry is far too small to exert any market leverage on global dye or pigment manufacture. With rare exceptions, all modern watercolor paints utilize pigments that were manufactured for use in printing inks, automotive and architectural paints, wood stains, concrete, ceramics and plastics colorants, consumer packaging, foods, medicines, textiles and cosmetics. Paint manufacturers buy very small supplies of these pigments, mill (mechanically mix) them with the vehicle, solvent and additives, and package them.
Many artists are confused or misled by labeling practices common in the art materials industry. The marketing name for a paint, such as "cobalt blue" or "emerald green", is often only a poetic color evocation or proprietary moniker; there is no legal requirement that it describe the pigment that gives the paint its color. To remedy this confusion, in 1990 the art materials industry voluntarily began listing pigment ingredients on the paint packaging, using the common pigment name (such as "cobalt blue" or "cadmium red"), and/or a standard pigment identification code, the generic color index name (PB28 for cobalt blue, PR108 for cadmium red) assigned by the Society of Dyers and Colourists (UK) and the American Association of Textile Chemists and Colorists (USA). This allows artists to choose paints according to their pigment ingredients, rather than the poetic labels assigned to them by marketers. Paint pigments and formulations vary across manufacturers, and watercolor paints with the same color name (e.g., "sap green") from different manufacturers can be formulated with completely different ingredients.
Watercolor paints are customarily evaluated on a few key attributes. In the partisan debates of the 19th century English art world, gouache was emphatically contrasted to traditional watercolors and denigrated for its high hiding power or lack of "transparency"; "transparent" watercolors were exalted. Paints with low hiding power are valued because they allow an underdrawing or engraving to show in the image, and because colors can be mixed visually by layering paints on the paper (which itself may be either white or tinted). The resulting color will changed depending on the layering order of the pigments. In fact, there are very few genuinely transparent watercolors, neither are there completely opaque watercolors (with the exception of gouache); and any watercolor paint can be made more transparent simply by diluting it with water. "Transparent" colors do not have titanium dioxide (white) or most of the earth pigments (sienna, umber, etc.) which are very opaque. The 19th century claim that "transparent" watercolors gain "luminosity" because they function like a pane of stained glass laid on paper -- the color intensified because the light passes through the pigment, reflects from the paper, and passes a second time through the pigment on its way to the viewer -- is false: watercolor paints do not form a cohesive paint layer, as do acrylic or oil paints, but simply scatter pigment particles randomly across the paper surface. Watercolors appear more vivid than acrylics or oils because the pigments are laid down in a more pure form with fewer fillers (such as kaolin) obscuring the pigment colors. Multiple layers of watercolor do achieve a very luminous effect because of less fillers obscuring the pigment particles.
Staining is another characteristic assigned to watercolor paints: a staining paint is difficult to remove or lift from the painting support after it has been applied or dried. Less staining colors can be lightened or removed almost entirely when wet, or when rewetted and then "lifted" by stroking gently with a clean, wet brush and then blotted up with a paper towel. In fact, the staining characteristics of a paint depend in large part on the composition of the support (paper) itself, and on the particle size of the pigment. Staining is increased if the paint manufacturer uses a dispersant to reduce the paint milling (mixture) time, because the dispersant acts to drive pigment particles into crevices in the paper pulp, dulling the finished color.
Granulation refers to the appearance of separate, visible pigment particles in the finished color, produced when the paint is substantially diluted with water and applied with a juicy brush stroke; pigments notable for their watercolor granulation include viridian (PG18), cerulean blue (PG35), cobalt violet (PV14) and some iron oxide pigments (PBr7). "Flocculation" refers to a peculiar clumping typical of ultramarine pigments (PB29 or PV15). Both effects display the subtle effects of water as the paint dries, are unique to watercolors, and are deemed attractive by accomplished watercolor painters. Regrettably the trend in commercial paints seems to be to suppress pigment textures in favor of homogeneous, flat color.
Commercial watercolor paints come in two grades: "Artist" (or "Professional") and "Student". Artist quality paints are usually formulated less fillers (kaolin or chalk) which results in richer color and vibrant mixes. Student grade paints have less pigment, and often are formulated using two or more less expensive pigments. Artist and Professional paints are more expensive but many consider the quality worth the higher cost.
As there is no transparent white watercolor, the white parts of a watercolor painting are most often areas of the paper "reserved" (left unpainted) and allowed to be seen in the finished work. To preserve these white areas, many painters use a variety of resists, including masking tape, clear wax or a liquid latex, that are applied to the paper to protect it from paint, then pulled away to reveal the white paper. White paint (titanium dioxide PW6 or zinc oxide PW4) is best used to insert highlights or white accents into a painting. If mixed with other pigments, white paints may cause them to fade or change hue under light exposure. White paint (gouache) mixed with a "transparent" watercolor paint will cause the transparency to disappear and the paint to look much duller. White paint will always appear dull and chalky next to the white of the paper, however this can be used for some effects.