Art Lesson - Watercolor Paper

How is watercolour paper made?

In the past all watercolour paper was made from linen (flax) waste or rags. After being pulverized and cleaned the resulting pulp is transferred to large vats. A mould consisting of a wire mesh stretched on a wooden frame is dipped in the water and shaken to align the fibers as the water drains through the mesh. When the strained pulp reaches the proper thickness the mould is inverted on to a felt 'blanket' to which the new sheet of paper clings. A new felt is layered on top of the paper and the hand moulding process is repeated, creating a layered stack of paper and felts. The stack is then put in a press to release the excess water. Hand made paper is distinctive in its randomly irregular surface and frayed deckled edges on all four sides.

Handmade papers are available today, but are generally more expensive than the machine made varieties. The machine made papers do offer consistent quality and texture and do to the manufacturing process they usually have a two sided deckle with the other two sides cut or torn to resemble a deckle edge.

The majority of modern papers use the term 'rag' to indicate any natural fiber, but primarily cotton fiber is used. Rag contents of less than 100% add manilla, flax, synthetic fibers or wood pulp to the blend. These are marketed as student grades.


High PH is a BAD thing

Papers made with wood or manilla contain a higher acid (PH) content and tend to degrade over time, becoming yellowed and brittle. Archival quality watercolour papers have a neutral PH value.

What about Synthetics?

Synthetic papers papers are made with fibers such as TYVEC. The surfaces are very durable, but you must alter your technical approach due to their unique absorbsion and working properties.

What is sizing?

Papers are traditionally sized with gelatine. The amount of sizing determines the amount of colour the paper takes into its structure. Heavier sizing allows more colour to stay on the surface and allows easier reworking of the paint. Internally sized paper has the sizing added in the vat before the paper is made. Tub sized papers are soaked in a sizing bath after the paper is made Tub sized paper is the preferred choice of watercolourists. A paper that is too heavily sized can resist your brush strokes. To remedy this sponge your paper with clear water once or twice. This will eliminate some of the surface sizing and make the surface more receptive. Papers that are stretched lose any excess sizing in the streching process.

Weighing the paper

The weight of a paper is determined by the weight in pounds per square meter. Traditional paper for watercolour range from 70 lbs. to over 300 lbs. in weight. A lighter weight paper (less than 140 lb. tends to warp extensively unless the paper is stretched wet on a frame as a canvas or wet on a board and taped with brown gummed tape. When dry the surface can be worked without warping due to water absorbsion.

The average weight used is 140 lb. This weight has minimal warping and is much less expensive than heavier weights. Another popular weight is 300 lb. paper. It offers even more resistance to warping and can withstand more aggressive scrubbing and working of the surface. If you try a new paper always test the surface to see if it is sized properly for your work. Over sizing can cause washes to bead up and not flow smoothly. To fix this problem use a clean sponge and water to gentle wash the entire surface then air dry the paper.

Watercolour papers of lighter weights are available in blocks. Blocks hold 15 to 20 sheets of watercolour paper on a stiff cardboard backing. The edges are bound together with a small area unbound for slipping a knife in to release the sheets as they are used. Paper in blocks tend to warp out and bulge in the middle when they are wet. Releasing three of the bound edges before you begin to paint will alieviate most of the problem for you.


There are Three Surface types:

	Hot Pressed: the surface is finely grained and smooth. It takes colour smoothly and allows for easier textured brush work. It is processed with high pressure as it is dried.
	Cold Pressed or 'Not' Pressed: this medium rough texture is preferred by most It takes colour smoothly also, but the tooth allows for slight irregularities and graining in washes.
	Rough: Is a coarse rough texture. This surface allows for maximum graining of washes and accidental highlights and texture.