Feb 26, 2019How to
What exactly makes a paper the right selection for use as a watercolour or fluid media surface? Paper is paper, is paper right?
Start with the sizing—and no, we don’t mean actual measurements. “Sizing” is a crucial treatment to papers, making them suitable for watercolour. While the sheet is being formed in manufacturing, a sizing is added to the paper pulp, which is commonly referred to as “internal sizing”. The sheet then is either externally sized by immersing the sheet in a water and sizing solution (referred to as “tub sizing”) or is spray surface coated (referred to as “external” or “surface sizing”). Many top professional brands boast both internal and external sizing, with lesser quality papers being only externally sized. Sizing is either gelatin (animal sourced, historically the original sizing) or starch (plant sourced) based, which also varies by manufacturer. Sizing aids the paper in absorbing moisture evenly, and allows the pigment to sit up on the surface where it refracts colour more brightly, instead of soaking in and giving a “dull” appearance. The colour then can easily be reworked due to the accessibility of the pigment remaining on the surface.
The name “paper” can sometimes be a misnomer in the world of art supplies, where all art papers are NOT manufactured from wood pulp. A high percentage of watercolor papers are either a 100% cotton “rag” paper (once made from trimmed cotton rags) or a cotton and alpha cellulose blend. Other papers may be made of wood pulp, alpha cellulose, or a combination therof. These contain lignins- a component in the plant that helps give the strength and rigidity to cell walls—but sadly attributes to breaking down of the paper as it becomes acidic over time. Cotton far exceeds pulp or other plant cellulose products, due to longer, stronger fibres that are more durable and naturally absorbent. These stand up to repeated erasing with underdrawings, scrubbing out painting mistakes, and taping and stretching before painting. Pricewise, wood pulp and alpha cellulose papers are more cost effective for the beginner, but come at the price of frustration due to being less durable, and unforgiving, and not ultimately archival.
Always look for buzzwords like lignin-free, acid-free, and archival in the descriptions of watercolour papers, to help protect the longevity of your work.
The “press” of a watercolour paper is more than just its surface texture. It actually is determined by the way that the paper is finished, as it is run through cylinders that are either heated or cooled. This creates the final paper texture. The purpose of texture in watercolour paper is to create a sense of depth for the pigment, as the peaks and valleys refract color differently, and add interest to the work.
Three very distinct, universal surfaces are available from most watercolour paper manufacturers:
Weight is important because lighter papers need stretching before use and may buckle or wrinkle when wet.
Heavy paper can absorb more water and rarely needs stretching. Paper weight is determined by measuring a ream (500 sheets) of a given size in pounds or grams per square meter (GSM). Light paper is anything less than 140 lb/300 gsm and heavy is 300-400 lb/600-850 gsm.
Paper weight really comes into play when working on your watercolour painting. The most standard paper for watercolour is typically 300gsm, can buckle and curl if not taped down or stretched, if you work with lots of wash techniques or cover large amounts of paper with water at the same time. 600gsm paper is thicker and will lay flat when even fully saturated, so some artists find the added expense a welcomed trade off to not having to stretch, tape, or simply deal with thinner paper antics. Paper lower weights than 300gsm tend to be less durable to work with, using a lot of washes, scrubbing, or erasing and are best used for pen and ink or drier watercolour techniques after being taped or stretched.
There are watercolour papers for every application and interest, from pads, to blocks, from half and full sheets, to cut pieces, in every quality grade and price range imaginable. Take the time to read about the products before purchasing, to find the ideal product and price point to suit your needs.