Paper Weight and Tooth: What the Numbers Mean

Paper is described with two ideas that sound technical and behave simply. Weight tells you how much fibre is in the sheet, usually as grams per square metre. Tooth tells you how rough the surface is. Together they decide whether a pencil whispers, a pen skips, or a wash buckles the page. You do not need a cabinet of papers. You need to match one sheet to the tool in your hand.

Weight, without the drama

A higher gsm means a heavier sheet. Sketchbook paper around 90 to 150 gsm is pleasant for dry drawing and miserable for a wet wash. Watercolour paper around 300 gsm can take a wash with less buckling, especially if you tape it down. Lighter watercolour sheets exist and often need stretching. The number is a guide, not a moral ranking. A heavy sheet that is poorly sized can still suck the life out of a wash.

Canvas, Board or Paper? sets paper among the wider choice of supports. This piece stays with the sheet itself. If you only draw in pencil, do not buy the heaviest watercolour paper out of anxiety. It will feel dead under a hard point. If you wash colour, do not expect a novel-weight sketchbook to stay flat.

Tooth: hot, cold and rough

Hot-pressed paper is smooth. Pen and fine pencil like it. Washes sit on it a little more starkly, and granulating colours have less texture to settle into. Cold-pressed paper has a moderate tooth and is the usual all-rounder for watercolour. Rough paper has a deep valley. Dry brush skips across the tops and looks broken and lively. A soft pencil on rough paper leaves a dark, grainy mark. A fine nib may catch.

Wet-on-Wet Watercolour Without Losing the Drawing depends on a sheet that can hold water. Tooth changes how that water looks, not only how long it sits. Try the same wash on two scraps before you decide the paint is at fault.

Sizing and the back of the sheet

Sizing is the glue that slows absorption. A hard-sized sheet gives you time. A soft, absorbent sheet drinks the first stroke. Some papers are sized for one face only. If washes bloom strangely, you may be working on the wrong side. A small watermark or a smoother back will often tell you. When in doubt, test both.

Ink and marker need a sheet that does not feather. Bleed-through is the related nuisance. If the line appears on the reverse, draw on one side or choose a heavier page. Keeping Sketchbook Pages Flat and Unsmudged is what to do after the choice. The choice itself belongs here, before the book is full of buckled ghosts.

Buy a sheet, not a mythology

Purchase two or three kinds and make the same small mark on each: a pencil gradient, a pen line, a flat wash. Label them with the gsm and the surface. Keep the scrap in the sketchbook. That page will outrank a catalogue. Student paper is fit for exercises. A better sheet earns its cost when you already know which tool you are feeding.

One ream of a paper you understand will improve the work more than six exotic pads you are afraid to cut. Match the tooth to the mark you want to see, and the weight to the amount of water you actually use.

Frequently asked questions

Is heavier paper always better? No. It is better for water. For a dry line, a moderate sketching sheet often feels more alive. Better means matched.

What does cold-pressed mean? The sheet was pressed less smooth than hot-pressed paper, so a tooth remains. You do not need the factory story. You need to feel the surface and watch a wash sit on it.

Can I paint on both sides? On a well-sized heavy sheet, often yes. On thin paper, the first wash may spoil the reverse. Test. A drawing on the back of a buckled wash is a discouraging surprise.