Watercolor or water–soluble pencils and crayons are a unique cross-over between drawing and painting. You draw with them as you would with any pencil or crayon, but then if you run a wet brush over your drawing, the color is dispersed and turns into a watercolor wash.
Watercolor pencils are specifically manufactured with a binder that dissolves in water.
Water-soluble pencils are available in a wide range of colors, as well as plain graphite pencils. Colored watercolor pencils aren’t graded like graphite pencils are (from 9B, the softest, to 9H, the hardest), but their softness does vary between brands so it may be worth buying a sample pencil from various brands to see which you prefer before you buy a set. The softer a watercolor pencil is, the easier it is to put color or pigment down on a paper.
Two variations on watercolor pencils available are woodless pencils (just the pencil ‘lead’ with a paper wrapper) and water-soluble crayons (like wax crayons, but they dissolve in water). Water-soluble crayons enable you to put down more pigment (or color) faster than a watercolor pencil, as they’re softer and broader.
Watercolor pencils look the same as ‘normal’ pencils, but if you check the lettering stamped on them you’ll see a little symbol to show they’re water soluble, such as a water droplet or a small brush, or the word ‘watercolor’. Of course, you can always just do a quick test on a scrap bit of paper to test.
Using a water-soluble pencil or crayon where you didn’t intend to can result in disaster if you use to paint over the drawing or sketch, smudging it. So if you mix your types of pencils up, always check! (Thought CO)