Wooden venetian blinds: 25mm, 35mm or 50mm slats, and tapes or cords?

Wider slats mean fewer of them, so the blind has fewer horizontal lines, a more open view when tilted, and a shorter stack of slats at the top when fully raised. They also need more depth: a 50mm slat tilted flat needs a recess of around 60mm to clear the glass and the handle. Narrower slats fit shallower recesses and suit smaller windows where 50mm would look oversized, but they stack taller and show more lines across the view.

The 50mm slat is what most people are picturing when they search for shutter blinds. On a window over about a metre wide it looks proportionate and generous, and with cloth tapes it reads as a solid, furnished piece rather than a utilitarian blind. It suits living rooms, dining rooms and main bedrooms. Its limits are depth, which rules out shallow uPVC recesses unless face fixed, and small windows, where it can look heavy.

The 35mm slat is the one we specify most often on standard bedroom and study windows around 800mm to 1,200mm wide. It fits most recesses, stacks reasonably, and looks neither dainty nor bulky. If you are unsure and the window is average sized, 35mm rarely disappoints.

The 25mm slat belongs on cottage windows, cloakrooms, narrow landing windows and anywhere the recess is shallow. It gives fine light control at close range and its small stack is an advantage on short windows. On a large window it produces too many lines and a lot of cord, so keep it for the openings it was designed for.

Every venetian is lifted by cords through holes in the slats. Cloth ladder tapes cover those holes with a strip of fabric on the front and back of the blind, which blocks the pinpricks of light through the holes and adds a second colour. They suit 50mm slats best and make the blind look more like a shutter. Cord ladders leave the slats visually lighter and are the usual choice on 25mm and 35mm. Neither is dearer by much; it is a look decision.

Real basswood is lighter, so wide blinds lift more easily, and it has a natural grain that takes stain beautifully. Faux-wood, a PVC or composite slat, is heavier but does not mind steam or splashes, so it is the right choice in kitchens, bathrooms and utility rooms. Painted finishes look almost identical in both; the difference shows in stained finishes and in how heavy a very wide blind feels to raise. Prices for both sit in the £140 to £220 per window range fitted.