Controlling Watercolour Washes on Sketchbook Paper

Why Thin Sketchbook Paper Buckles (and Why It Isn't Your Fault)

Most sketchbooks sold in the UK sit somewhere between 90gsm and 140gsm. That's perfectly lovely for pencil, pen and coloured pencil, but it was never really designed to drink water. The moment a wet wash hits the surface, the paper fibres swell. As they dry they shrink again, and if the drying is uneven from one part of the page to another, the sheet has nowhere to go but up and down. That's cockling — the rippled, wave-like surface that makes a finished page look rumpled.

There's a second culprit too: sizing. Cheaper sketchbook papers carry a light internal size, which means water soaks straight in and spreads sideways with very little control. Better watercolour papers are more heavily sized, so the paint sits on the surface long enough for you to move it around. You can't change the paper you already own, but you can absolutely change how much water you ask it to cope with.

Get Your Water-to-Paint Ratio Right

Almost every buckled page comes down to too much water, not too little paint. A useful benchmark: a wash should have the consistency of skimmed milk. If it looks like tea, it's too weak and will need endless layers. If it looks like double cream, it won't flow.

Try this before you commit brush to page:

• Mix your colour in the palette well, then touch the brush to a scrap of kitchen towel. A faint, even stain is right. A spreading wet blot means too much water.
• Keep two water pots — one for rinsing brushes, one for clean water. Murky rinse water sneaks into your mixes and dulls every colour.
• Load the brush, then wipe off the excess on the rim of the pot or a tissue. A brush that drips will flood the page.
• For delicate work, use a smaller brush than you think you need. Big brushes hold big puddles.

Laying a Clean Wash, Stroke by Stroke

The trick on thin paper is speed and restraint. Don't pre-wet the page — that's a technique for heavy watercolour paper and it will almost certainly buckle a sketchbook. Instead, work dry-on-dry and let the wetness come from your brush alone.

Tilt your sketchbook very slightly towards you. Load the brush, then lay a single horizontal stroke across the top of the shape you're filling. Don't scrub. Immediately reload and lay the next stroke just below it, letting the two edges touch so the paint merges. Keep a small bead of paint at the bottom of each stroke and guide it downwards. When you reach the bottom, rinse the brush, squeeze it damp, and lift off any excess bead with a light touch.

The hardest habit to break is going back over a stroke that's already starting to dry. Resist it. Re-working wet-into-damp on thin paper lifts the fibres and leaves a scuffed, patchy mess. If a wash isn't right, let it dry completely and glaze over it instead.

Work in Small Sections and Respect Drying Time

A sketchbook page isn't a full sheet of watercolour paper, and it doesn't have to be painted all at once. Divide the composition into two or three areas and finish one before starting the next. This keeps the total amount of water on the sheet at any one moment much lower.

Drying aids that genuinely help:

• A hairdryer on the cool setting, held at least 20cm away. Warm air can drive moisture into the paper unevenly.
• Patience — most thin-paper washes are touch-dry in five to ten minutes on a windowsill.
• Working on a warm, dry day rather than a humid one. Damp British weather slows drying and encourages spreading.

Keeping the Page Flat While You Work

You don't need to stretch paper for a sketchbook, but you do need to stop the edges curling inwards as they dry. A few simple habits make a real difference.

• Run a strip of low-tack masking tape along the outer edges of the page, or at least across the corners. Peel it off at a shallow angle once everything is bone dry.
• Clip the sketchbook to a lightweight drawing board with bulldog clips. The board gives the page something to lie against.
• Paint away from the spine. Water pooling in the gutter is the fastest way to a soggy, wavy centre.
• Close the book only when the page is completely dry. A closed book traps moisture and presses ripples permanently into the sheet.

Rescuing a Page That's Already Rippled

If a page has cockled, all is not lost. Lightly mist the back of the sheet with clean water — a fine spray, not a soaking — then close the book and weight it under a stack of heavy books for a few hours, or overnight. The fibres relax and dry flat under pressure. For stubborn pages, place a sheet of clean greaseproof paper either side and press with a cool iron on the very lowest setting, checking constantly.

The gentler approach is simply to accept a little texture. A slightly wavy page, painted with confidence and clean colour, looks far better than a flat page covered in mud. Be kind to your sketchbook, but don't be timid with it.