What Makes a Small Room Look Bigger: 5 Decorating Myths Debunked

Myth: White (or at least, light) paint is a must

Truth: A rich colour on walls and ceilings fools the eye. You won’t feel closed in, said interior designer Sindhu Peruri, of Los Altos, Calif., because when darker paint is used to dissolve a sense of defined geometry, powder rooms and closet-sized bedrooms will appear larger. Playing down architectural details helps too. Hadley Wiggins, a designer in Peconic, N.Y., said she plays with the perception of a room’s size by painting window sashes and trim the same colour as the walls, “allowing the eye to travel continuously instead of stopping on some jarring focal point or moment of contrast.”

Myth: Art shouldn’t dwarf a room

Truth: Use oversize art to fake a view. Even the laws of proportionality can be broken when maximizing petite spaces, said Brandon Schubert, an interior designer in London. “Treat art like a window,” he advised. And while you’re at it, look for paintings with vanishing points. “A lot of contemporary art feels very flat, but more-traditional art has perspective,” he said. He often hangs landscapes to add visual depth to even the tiniest of London loos. You can achieve this effect with either a single substantial piece or a gallery installation, said Ms. Salvesen. As long as the result “looks and feels generous,” she said, the space will, too.

Myth: Choose right-angled furniture so as not to waste space

Truth: Curved furniture adds movement and majesty. A trim floor plan often brings out a tendency to tuck in squared-off elements in a tight Jenga-like fashion to “save” square footage. But interior designer Juliana Vasconcellos, based in Rio de Janeiro, proposed that homeowners choose furniture that swooshes. “Normally the rule is to run from the curved sofa, but it gives a sensation of movement, and the idea of a bigger room,” she said. A rounded coffee or dining table has the same effect. At the least, said Seattle interior designer Heidi Caillier, consider seating with scroll arms or a gently curved back, details which will smooth out choppiness. “You can still have curviness on a sofa without it being fat,” she said.

Myth: Patterns will make a little space feel busy and coffin-like.

Truth: A figured wallpaper creates depth. Like dark paint, prints obscure corners, “almost creating a trompe l’oeil effect,” said Mr. Schubert. Opt for midsize to large-scale motifs. Minute prints, while quaint and cozy, can magnify a room’s tininess. For the less daring, even the subtle cross-hatching of grass cloth will add depth to shallow spaces. Laying down a striped carpet can have a similar result. “It stretches the floor,” said Mr. Schubert. He suggests wall-to-wall carpet, not rugs, which will leave bitty, busy borders.

Myth: Slick, modern finishes and lots of breathing room help a diminutive space feel less confining

Truth: The cosseting effect of soft furnishings and layered textures makes you feel small—and the room feel large. Ms. Caillier said she aims to create “a jewel box” and advised against “lots of clean lines.” Instead, she suggests plush window treatments, furniture with handworked elements and layers of nubbly textiles. “Each piece on its own should sing,” she said, explaining that when everything from a cushion to a side table is “cozy and considered,” the room takes on an enveloping warmth that suggests a larger scale. Window drapes can play double duty in low-ceilinged digs. Ms. Caillier suggests hanging them as far up as possible to lengthen the wall.