What Is Watercolor?
Jan 27th, 2008 by Jean Littman
Watercolor can be roughly divided into pure or transÂÂparent color and opaque color.
Watercolors are made with pure pigment mixed with gums or glues, usually gum arabic for transparent color and gums and emulsions for opaque color. The emulsions here would be egg yolk, casein and linseed oil and glue (parchment clippings). The gums would probably be a size made from rabbit skin, parchment clippings, gum arabic or gum tragacanth.
All the colors used in painting start off first as a powder made from a vegetable or mineral base. If you add water to the powder, you could produce washes and paint with them. However, when they are dried, the color would return to being powder and fall off.
To hold the powder together and cause it to stick permanently to the paper or canvas you have to use a binder in order to fix them. In watercolors you use those binders that will dissolve in water, i.e. glues and emulsions. In oil paint you bind the pigments with oils and these are dissolved in turpentine.
Pastels come in powder form too. The binder is usually gum tragacanth. They are rolled out into sticks and left to dry.
White is not used in transparent watercolor. The paper itself acts as the white. You will see that the more fluidly you handle transparent watercolor, the more brilliant are your results; and in any pure white passages the paper is left untouched. The more you over-paint the less brilliant your work becomes.
With opaque watercolor it is different. You can use opaque colors transparently or not as you wish, by thinning with more water. White can be used constantly for over-painting and for reworking any passages. Most opaque color has a white base added to it and in the cheaper variety this tends to become chalky and dead-looking.
