Watercolour paint consists of four principal ingredients:
- pigments, natural or synthetic, mineral or organic;
- Arabic gum as a binder to hold the pigment in suspension and fix the pigment to the painting surface;
- additives like glycerin, ox gall, honey, preservatives: to 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, watercolours, gouaches and modern acrylic paints.
The term watercolour refers to paints that use water soluble, complex carbohydrates as a binder. Originally (16th to 18th centuries) watercolour 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.
Bodycolour refers to paint that is opaque rather than transparent, usually opaque watercolour, which is also known as gouache. Modern acrylic paints are based on a completely different chemistry that uses water soluble acrylic resin as a binder.
Watercolour painters before c.1800 had to make paints themselves using pigments purchased from an apothecary or specialised “colour man”; the earliest commercial paints were small, resinous blocks that had to be wetted and laboriously “rubbed out” in water. William Reeves (1739–1803) set up in business as a colour man about 1766. In 1781 he and his brother, Thomas Reeves, were awarded the Silver Palette of the Society of Arts, for the invention of the moist watercolour paint-cake, a time-saving convenience the introduction of which coincides with the “golden age” of English watercolour painting.
Modern commercial watercolour 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 (favoured 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.
Thanks to modern industrial organic chemistry, the variety, saturation (brilliance) and permanence of artists’ colours 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 watercolour paints utilise pigments that were manufactured for use in printing inks, automotive and architectural paints, wood stains, concrete, ceramics and plastics colourants, 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.
If you would like to learn more about watercolour paint and how to use it. Come to Basic Water Colour Class with Diane!
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