Although watercolor painting is extremely old, dating perhaps to the cave paintings of paleolithic Europe, and has been used for manuscript illumination since at least Egyptian times but especially in the European Middle Ages, its continuous history as an art medium begins in the Renaissance. The German artist Albrecht Dürer (1471-1528) who painted several fine botanical, wildlife and landscape watercolors, is generally considered among the earliest exponents of the medium. 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 (small scale design drawings). Among 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 and wildlife illustrations are perhaps the oldest and most important tradition in watercolor painting. Botanical illustrations became popular in the Renaissance, both as hand tinted woodblock illustrations in books or broadsheets and as tinted ink drawings on vellum or paper. Botanical artists have always been among 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
Materials
Paint
Paints comprise 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 lack of "transparency" or hiding power; "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[citation needed] -- 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[citation needed]. 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.
[edit] Brushes
A brush consists of three parts: the tuft, the ferrule and the handle. The tuft is a bundle of animal hairs or synthetic fibers tied tightly together at the base; the ferrule is a metal sleeve that surrounds the tuft, gives the tuft its cross sectional shape, provides mechanical support under pressure, and protects from water the glue joint between the trimmed, flat base of the tuft and the lacquered wood handle, which is typically shorter in a watercolor brush than in an oil painting brush, and also has a distinct shape -- widest just behind the ferrule and tapering to the tip. When painting, painters typically hold the brush just behind the ferrule for the smoothest brushstrokes.
Brushes hold paint (the "bead") through the capillary action of the small spaces between the tuft hairs or fibers; paint is released through the contact between the wet paint and the dry paper and the mechanical flexing of the tuft, which opens the spaces between the tuft hairs, relaxing the capillary restraint on the liquid. Because thinned watercolor paint is far less viscous than oil or acrylic paints, the brushes preferred by watercolor painters have a softer and denser tuft. This is customarily achieved by using natural hair harvested from farm raised or trapped animals, in particular sable, squirrel or mongoose. Less expensive brushes, or brushes designed for coarser work, may use horsehair or bristles from pig or ox snouts and ears. However, as with paints, modern chemistry has developed many synthetic and shaped fibers that rival bristle and even hair for softness and flexibility. Until fairly recently, nylon brushes could not hold a reservoir of water at all so they were extremely inferior to natural bristles. In the past decade or so, each nylon bristle now has many small "hairs" off of it, each of which can hold a drop of water. Many artists now prefer synthetic brushes because of their superior points and durability.
There is no market regulation on the labeling applied to artists' brushes, but most watercolorists prize brushes from kolinsky (Russian or Chinese) sable. The best of these hairs have a characteristic reddish brown color, darker near the base, and a tapering shaft that is pointed at the tip but widest about halfway toward the root. Squirrel hair is quite thin, straight and typically dark, and makes tufts with a very high liquid capacity; mongoose has a characteristic salt and pepper coloring. Bristle brushes are stiffer and lighter colored. "Camel" is sometimes used to describe hairs from several sources (none of them a camel).
Natural and synthetic brushes are sold with the tuft shaped for different tasks. Among the most popular are:
- Rounds. The tuft has a round cross section but a tapering profile, widest near the ferrule (the "belly") and tapered at the tip (the "point"). These are general purpose brushes that can address almost any task.
- Flats. The tuft is compressed laterally by the ferrule into a flat wedge; the tuft appears square when viewed from the side and has a perfectly straight edge. "Brights" are flats in which the tuft is as long as it is wide; "one stroke" brushes are longer than their width. "Sky brushes" or "wash brushes" look like miniature housepainting brushes; the tuft is usually 3 cm to 7 cm wide and is used to paint large areas.
- Mops (natural hair only). A round brush, usually of squirrel hair and, decoratively, with a feather quill ferrule that is wrapped with copper wire; these have very high capacity for their size, especially good for wet in wet or wash painting; when moist they can wick up large quantities of paint.
- Filbert (or "Cat's Tongue", hair only). A hybrid brush: a flat that comes to a point, like a round, useful for specially shaped brush strokes.
- Rigger (hair only). An extremely long, thin tuft, originally used to paint the rigging in nautical portraits.
- Fan. A small flat in which the tuft is splayed into a fan shape; used for texturing or painting irregular, parallel hatching lines.
- Acrylic. A flat brush with synthetic bristles, attached to a (usually clear) plastic handle with a beveled tip used for scoring or scraping.
A single brush can produce many lines and shapes. A "round" for example, can create thin and thick lines, wide or narrow strips, curves, and other painted effects. A flat brush when used on end can produce thin lines or dashes in addition to the wide swath typical with these brushes, and its brushmarks display the characteristic angle of the tuft corners.
The size of a round brush is designated by a number, which may range from 0000 (for a very tiny round) to 0, then from 1 to 24 or higher. These numbers refer to the size of the brass brushmakers' mould used to shape and align the hairs of the tuft before it is tied off and trimmed, and as with shoe lasts, these sizes vary from one manufacturer to the next. In general a #12 round brush has a tuft about 2 to 2.5 cm long; tufts are generally fatter (wider) in brushes made in England than in brushes made on the Continent: a German or French #14 round is approximately the same size as an English #12. Flats may be designated either by a similar but separate numbering system, but more often are described by the width of the ferrule, measured in centimeters or inches.
In general, natural hair brushes have superior snap and pointing, a higher capacity (hold a larger bead, produce a longer continuous stroke, and wick up more paint when moist) and a more delicate release. Synthetic brushes tend to dump too much of the paint bead at the beginning of the brush stroke and leave a larger puddle of paint when the brush is lifted from the paper, and they cannot compete with the pointing of natural sable brushes and are much less durable. On the other hand they are typically much cheaper than natural hair, and the best synthetic brushes are now very serviceable; they are also excellent for texturing, shaping, or lifting color, and for the mechanical task of breaking up or rubbing paint to dissolve it in water.
A high quality sable brush has five key attributes: pointing (in a round, the tip of the tuft comes to a fine, precise point that does not splay or split; in a flat, the tuft forms a razor thin, perfectly straight edge); snap (or "spring"; the tuft flexes in direct response to the pressure applied to the paper, and promptly returns to its original shape); capacity (the tuft, for its size, holds a large bead of paint and does not release it as the brush is moved in the air); release (the amount of paint released is proportional to the pressure applied to the paper, and the paint flow can be precisely controlled by the pressure and speed of the stroke as the paint bead is depleted); and durability (a large, high quality brush may withstand decades of daily use).
Most natural hair brushes are sold with the tuft cosmetically shaped with starch or gum, so brushes are difficult to evaluate before purchasing, and durability is only evident after long use. The most common failings of natural hair brushes are that the tuft sheds hairs (although a little shedding is acceptable in a new brush), the ferrule becomes loosened, or the wood handle shrinks, warps, cracks or flakes off its lacquer coating.
Every watercolor painter works in specific genres and has a personal painting style and "tool discipline", and these largely determine his or her preference for brushes. Artists typically have a few favorites and do most work with just one or two brushes. Brushes are typically the most expensive component of the watercolorist's tools, and a minimal general purpose brush selection would include:
- 4 round (for detail and drybrush)
- 8 round
- 12 or 14 round (for large color areas or washes)
- 1/2" or 1" flat
- 12 mop (for washes and wicking)
- 1/2" acrylic (for dissolving or mixing paints, and scrubbing paints before lifting from the paper)
Reputable watercolor brush manufacturers include DaVinci, Escoda, Isabey, Raphael, Kolonok, Robert Simmons and Winsor & Newton. As with papers and paints, it is common for retailers to commission brushes under their own label from an established manufacturer. Among the best of these are Cheap Joe's, Daniel Smith, Dick Blick and Utrecht.
[edit] Paper
Most watercolor painters before c.1800 had to use whatever paper was at hand: Thomas Gainsborough was delighted to buy some paper used to print a Bath tourist guide, and the young David Cox preferred a heavy paper used to wrap packages. James Whatman first offered a wove watercolor paper in 1788, and the first machinemade ("cartridge") papers from a steam powered mill in 1805.
All art papers can be described by eight attributes: furnish, color, weight, finish, sizing, dimensions, permanence and packaging. Watercolor painters typically paint on paper specifically formulated for watermedia applications. Fine watermedia papers are manufactured under the brand names Arches, Fabriano, Hahnemuehle, Lanaquarelle, Saunders Waterford, Strathmore, Winsor & Newton and Zerkall; and there has been a recent remarkable resurgence in handmade papers, notably those by Twinrocker, Velke Losiny, Ruscombe Mill, and St. Armand.
The traditional furnish or material content of watercolor papers is cellulose, a structural carbohydrate found in many plants. The most common sources of paper cellulose are cotton, linen, or alpha cellulose extracted from wood pulp. To make paper, the cellulose is wetted, mechanically macerated or pounded, chemically treated, rinsed and filtered to the consistency of thin oatmeal, then poured out into paper making moulds. In handmade papers, the pulp is hand poured ("cast") into individual paper moulds (a mesh screen stretched within a wood frame) and shaken by hand into an even layer. In industrial paper production, the pulp is formed by large papermaking machines that spread the paper over large cylinders -- either heated metal cylinders that rotate at high speed (machinemade papers) or wire mesh cylinders that rotate at low speed (mouldmade papers). Both types of machine produce the paper in a continuous roll or web, which is then cut into individual sheets.
The basis weight of the paper is a measure of its density and thickness. It is described as the gram weight of one square meter of a single sheet of the paper, or grams per square meter (gsm). Most watercolor papers sold today are in the range between 280gsm to 640gsm. (The previous Imperial system, expressed as the weight in pounds of one ream or 500 sheets of the paper, regardless of its size, is now obsolete.) Watercolor papers are typically almost a pure white, sometimes slightly yellow, though many tinted or colored papers are available. An important diagnostic is the rattle of the paper, or the sound it makes when held aloft by one corner and shaken vigorously. Papers that are dense and made from heavily macerated pulp have a bright, metallic rattle, while papers that are spongy or made with lightly macerated pulp have a muffled, rubbery rattle.
All papers obtain a texture from the mould used to make them: a wove finish results from a uniform metal screen (likea window screen); a laid finish results from a screen made of narrowly spaced horizontal wires separated by widely spaced vertical wires. The finish is also affected by the methods used to wick and dry the paper after it is "couched" (removed) from the paper mold or is pulled off the papermaking cylinder.
Watercolor papers come in three basic finishes: hot pressed (HP), cold press (CP, or in the UK "Not", for "not hot pressed"), and rough (R). These vary greatly from manufacturer to manufacturer.
- Rough papers are typically dried by hanging them like laundry ("loft drying") so that the sheets are not exposed to any pressure after they are couched; the wove finish has a pitted, uneven texture that is prized for its ability to accent the texture of watercolor pigments and brushstrokes.
- Cold pressed papers are dried in large stacks, between absorbent felt blankets; this acts to flatten out about half of the texture found in the rough sheets. CP papers are valued for their versatility.
- Hot pressed papers are cold pressed sheets that are passed through heated, compressing metal cylinders (called "calendaring"), which flattens amost all the texture in the sheets. HP papers are valued because they are relatively nonabsorbent: pigments remain on the paper surface, brightening the color, and water is not absorbed, so it can produce a variety of water stains or marks as it dries.
These designations are only relative; the CP paper from one manufacturer may be rougher than the R paper from another manufacturer. Fabriano even offers a "soft press" (SP) sheet intermediate between CP and HP.
Watercolor papers are traditionally sized, or treated with a substance to reduce the cellulose absorbency. Internal sizing is added to the paper pulp after rinsing and before it is cast in the paper mould; external or "tub" sizing is applied to the paper surface after the paper has dried. The traditional sizing has been gelatin, gum arabic or rosin, though modern synthetic substitutes (alkyl-ketene dimers such as Aquapel) are now used instead. The highly absorbent papers that contain no sizing are designated waterleaf.
Most art papers are sold as single sheets of paper in standard sizes. Most common is the full sheet (22" x 30"), and half sheets (15" x 22") or quarter sheets (15" x 11") derived from it. Larger (and less standardized) sheets include the double elephant (within an inch or two of 30" x 40") and emperor (40" x 60"), which are the largest sheets commercially available. Papers are also manufactured in rolls, up to about 60" wide and 30 feet long. Finally, papers are also sold as watercolor "blocks" -- a pad of 20 or so sheets of paper, cut to identical dimensions and glued on all four sides, which provides high dimensional stability and portability, though block papers tend to have subdued finishes. The painter simply works on the exposed sheet and, when finished, uses a knife to cut the adhesive around the four sides, separating the painting and revealing the fresh paper underneath.
Finally, the best art papers are designated archival, meaning they will last without significant deterioration for a century or more. Archival means that the papers are made entirely of high alpha cellulose or 100% cotton or linen fiber (that is, they are lignen free, as lignen causes the darkening and embrittlement under light exposure), pH neutral (meaning there is no residual acidity left from the chemical processing of the pulp), buffered (a small quantity of an alkaline compound, usually calcium carbonate, is added to the furnish to neutralize the effect of atmospheric acids), and free of any artificial paper brighteners or whiteners (e.g., ultraviolet dyes). The content designations "100% cotton" or "100% cotton rag" have little significance to the actual quality or handling attributes of the paper. (A wide range of papers using alternative plant fibers, some of them not archival, are available from Asian manufacturers; some watercolor painters even employ sheets of printable plastic, sold under brand names such as Yupo.)
A useful test of paper quality is simply to burn a small piece of the paper in an ashtray: pure cellulose completely burns away to a wispy, whitish gray ash. The absorbency of a paper is assessed by licking it. The mechanical strength of the paper is assessed by repeatedly folding it back and forth along a single crease. The stability of the paper (amount of cockling when soaked) and its response to lifting paint (the paper should not shred or tear) is best tested by making a painting on it.
All cellulose fibers absorb moisture and expand along the length of the fiber when wet; this produces the familiar buckling or warping called cockling. Evenly wetted, machinemade papers typically curl along one dimension, revealing the curvature of the cylinder they were formed on; some mouldmade papers and all handmade papers cockle in a random, uneven pattern. Handmade papers typically have four natural deckles (feathery, uneven edges) left by the paper mould; mouldmade papers have two natural deckles along the edges of the web, and two simulated deckles produced by cutting the sheet with a jet of compressed water; machinemade papers have no deckles.
In the 19th century, before modern high quality and heavy weights of paper were available, watercolor painters preferred to "stretch" papers before painting on them, to minimize or eliminate cockling and to provide a firm painting support. The paper was first completely immersed in water for 10-15 minutes, then laid completely flat on a board. The paper edges were fixed with gummed tape, starch glue or tacks, and the paper was left to dry. (As paper dries it shrinks, producing a high tension across the paper surface; when painted on, this tension takes up the expansion produced by the paper cockling, so that the paper remains flat.) When the painting was finished, the gummed or glued edge of the paper, including the deckle (which was considered unsightly) was trimmed away. Many watercolor painters still stretch their papers, but because natural deckles are appreciated today for their decorative, handmade effect, the modern preference is to work on unstretched papers, either by using a heavier weight of paper, by allowing paper to dry out before it becomes too saturated, or by exploiting the artistic effects that cockling can produce.