Will Your Sketchbook Survive a Watercolor Wash

A regular sketchbook will not survive a watercolor wash, and a mixed media sketchbook will survive only a modest version of one. The difference comes down to weight. According to the sketchbook maker JIANXI, the paper in an ordinary pencil sketchbook runs 90 to 120 gsm. Most watercolor guides treat 300 gsm as the working standard, roughly three times as heavy.

That gap shows up on the first wet evening. A light glaze on a 160 gsm mixed media page will cockle and mostly recover. A saturated wash on a 100 gsm drawing page will buckle and pool, and in a bound book it can print onto the page behind it. The question usually comes up when someone with a half-filled sketch journal buys a first pan set and wonders whether the paper they already own will do.

Water soaks into paper fibers and makes them swell. The wet part of the sheet grows and the dry part does not, so the page has to rise somewhere. A heavier sheet has more material to resist that movement. A lighter one simply gives way. The guide at Best Watercolor Paper states that even a moderate wet-on-wet wash will buckle 90 lb (about 190 gsm) paper, and that is already heavier than most drawing sketchbooks.

Once a page buckles, the problem gets worse as you paint. The sheet forms what the same guide calls "hills and valleys". Water runs into the valleys, so those spots stay wet longer and swell further, and the wash dries in blotches.

Weight is only part of it. Watercolor paper is also sized, meaning it is treated to control how much water it absorbs. Carissa Duemig at Art Craft Love explains that dedicated watercolor paper is sized internally and externally "so water beads and dries evenly rather than soaking into fibers". Drawing paper that soaks up water instead of holding it on the surface swells faster and pills sooner.

The fiber matters too. Cotton rag paper at 140 lb or heavier resists buckling well, while wood-pulp papers buckle more readily, "it's the nature of the beast", as one WetCanvas member put it. Binding adds a final complication. A loose sheet can at least spread out evenly. A bound page is held at its spine, so it can only rise unevenly.

In one WetCanvas thread, an artist describes a homemade sketchbook of 220 gsm cartridge paper. That is heavier than any pencil sketchbook, yet "it curves so much that sometimes the washes end up on the next page below." The weight was fine. The wood-pulp fiber and the lack of sizing for washes were not.

In a second thread, a painter taped down a 16 x 20 inch sheet of Bristol vellum, which is a smooth drawing board. Two overlapping washes with too much water still raised a bubble, and it distorted the pencil drawing underneath. Taping holds the edges of a sheet, but the middle can still swell.

The third case is mixed media pads as a category. Artsydee puts 160 gsm as the minimum for mixed media use and calls 160 to 190 gsm suitable for light washes combined with drawing. The Studio Manager, reviewing seven such pads, said plainly that "none of these is a true watercolor pad" and warned that the cheapest of them were prone to buckling under watercolor.

There is a strong counterargument, and it comes from experienced sketchers. A sketchbook page is small, so the amount of water on it is limited. One forum poster noted that inexpensive pages "flatten out after a while" once the book is closed, and many sketchers simply accept a little rippling as part of working in a sketchbook. All of that is true. But it supports a narrower claim than it seems to. These painters are describing restrained sketching with little water, not a saturated wash, and the advice they give is to use less water, which leads back to the same conclusion.

It also helps to tell temporary rippling apart from permanent warping. Ordinary cockling eases as the page dries. Warping that remains after the page is fully dry usually means one area stayed wet much longer than the rest. Weight is not a measure of overall quality either. As our paper weight explainer sets out, weight mostly describes stiffness. That is why a heavy cartridge paper can still fail under a wash.

Most sketchbooks print their weight on the cover, and that number tells most of the story.

• Under 160 gsm: keep it to dry media. If you must add color, use watercolor pencils and wet them afterward, which puts far less water on the page than a brushed wash.
• 160 to 190 gsm, mixed media: glazes are workable. Forum advice is to mix paint to a "milk to cream" consistency, with more pigment and less water, and to tape the page edges before painting. Better still, remove the page and tape it to a board so any buckling cannot spread to the facing page.
• After the damage: let the page dry completely, then spray the back lightly with water, place it between sheets of clean paper, and weight it with heavy books. Posters report it comes out flat in a couple of hours.

For genuine washes, no technique makes up for missing weight and sizing. A loose sheet of lighter watercolor paper can be held flat by stretching it on a board, but a bound drawing page cannot be. Before choosing paper, decide how much water each painting will use. If the answer is a full wash, the paper needs to be around 300 gsm, and a sketchbook built for pencil will not do.