Choosing watercolour paper: cotton, cellulose and what the numbers mean

Most of the frustration people feel with watercolour has nothing to do with their painting and everything to do with their paper. Pigment that refuses to blend, edges that bloom, a sheet that buckles into hills the moment it gets wet: all of this is the paper, not you.

Here is what we tell people at the counter.

Fibre first: cotton or cellulose

100% cotton paper (Arches, Saunders Waterford, Fabriano Artistico, Baohong Academy, Chitrapat) absorbs water slowly and evenly. Washes stay wet longer, so you can push pigment around, lift it back out and layer glazes without disturbing what is underneath. It is the paper most professional painters use, and it is the paper that makes "difficult" techniques suddenly feel easy.

Cellulose (wood pulp) paper (Canson XL, Fabriano 1264, Brustro, most student pads) is sized to behave like cotton for the first wash, but it dries faster and lifts less kindly. It is a good place to learn and an excellent place for sketches, studies and colour swatches. Just do not judge your skill by how it behaves with wet-in-wet.

If you are moving from a student pad to your first cotton sheet, expect a week of re-learning how much water to use. It is worth it.

Weight: 190, 300 or 640 gsm

Paper weight is written in grams per square metre (gsm) or pounds (lb).

• 190 gsm / 90 lb needs stretching or taping down for anything wetter than a light wash.
• 300 gsm / 140 lb is the everyday standard. It buckles a little with heavy washes but flattens as it dries, especially if you tape all four edges.
• 640 gsm / 300 lb is almost board-like. No stretching, no buckling, and it takes aggressive scrubbing and masking fluid. Expensive, but a joy for finished pieces.

Surface: hot press, cold press, rough

• Hot press (HP) is smooth. Ink and fine detail sit crisply on it. Washes dry with visible edges, which some painters love and others fight.
• Cold press (CP / NOT) has a gentle texture. It is the all-rounder and the one to buy if you only buy one.
• Rough has a pronounced tooth that breaks up dry-brush strokes beautifully and holds a lot of water. Lovely for landscapes and loose work.

Pads, blocks, sheets and rolls

A pad is glued on one edge and is the cheapest way to buy paper. A block is glued on all four edges, so the sheet stays flat while you paint and you slice it free afterwards. Loose sheets (usually 56 x 76 cm) are the best value per square centimetre and can be cut down. Rolls are for large work or for studios that go through a lot of paper.

At Charco we stock Arches, Saunders Waterford, Fabriano, Canson, Strathmore, Clairefontaine, Baohong, Anupam, Brustro and Chitrapat across these formats. Come in and feel the surfaces side by side. We keep open sheets on the counter for exactly that reason.