How light colour changes the look of walls and furniture

The same paint looks different depending on the colour of the light. How light affects walls, furniture and textiles, and what to watch out for when redecorating.

A pale grey that looked lovely in the paint shop suddenly turns greenish or purplish on your wall at home. A new sofa looks darker or duller than in the showroom. In most cases the paint or fabric has not “changed”; the light has. Colour does not live in the object itself but in how light reflects off its surface.

How colour depends on light

Every surface absorbs some of the light that falls on it and reflects the rest. Red fabric looks red because it reflects red wavelengths. If the light itself is weak in red, the fabric has little to reflect and looks dull. That is why the spectrum of the light, meaning both its colour temperature and its colour rendering index, directly changes the colours of an interior.

There are two separate effects. Colour temperature shifts the whole scene towards warm or cool. CRI shows how accurately individual colours are rendered. The two need to be considered together.

How warm light shows colours

Light at 2700–3000K has strong red and yellow components. As a result:

• beige, cream, terracotta, mustard and red-brown tones look fuller and cosier;
• the natural golden colour of wood is enhanced;
• a white wall turns cream, and a grey wall can drift towards warm beige;
• blue, turquoise and cool green tones become muted and slightly grey.

A warm-palette interior stays harmonious under warm light. A cool-palette interior of white, grey and blue can lose its crispness under it.

How neutral and cool light show colours

At 4000K and above, the blue component increases:

• white walls look bright and clean;
• blue, green and grey tones become clearer;
• beige and cream can look grey-yellow, sometimes even “dirty”;
• wood loses its warmth, and red-brown furniture looks grey-brown;
• skin looks paler.

In Scandinavian-style, white and grey, minimalist interiors, neutral light is often closer to the look the designer intended.

The most common mistake when choosing paint

Paint charts and sample cards are chosen under the shop's own lighting. Shops are usually lit with cool or neutral light, while at home warm bulbs are on in the evening. The right sequence is therefore:

• Bring the sample card or a small tester pot home.
• Check it on the wall itself, in different places: by the window and deeper in the room.
• Look at it in daylight and in the evening under the lamps you will actually use in that room.
• If possible, paint a large test patch, at least the size of an A4 sheet; a small card shows too little colour.
• If you plan to change the lamps later, run the test with the new lamp.

“Neutral” paints such as light grey and beige are the most sensitive to light, because small amounts of green, blue or pink pigment in them come forward depending on the light.

The sheen of the paint also affects the result. Matt paint scatters light and shows colour evenly. On satin and gloss surfaces you see a reflection of the lamp itself, and at those points the colour looks lighter and closer to the tint of the light. The difference is especially noticeable where light grazes along a wall from the ceiling or from below, so it is best to test with the same sheen as the final paint.

Furniture and textiles

The same rule applies to sofas, curtains and rugs. Taking a fabric sample home and looking at it under your own evening light is more reliable than how it looked in the shop. Similar dark colours such as navy and black, or dark green and brown, look almost identical under light with poor colour rendering; a high-CRI lamp reveals the difference.

Planning light and colour together

Before redecorating, it helps to ask: what light will this room mainly have? Choosing a palette that looks good under warm light for evening living rooms and bedrooms, and one that looks good under neutral light for kitchens, bathrooms and studies, prevents a lot of disappointment later.

On the Zaferoğlu Elektrik site there is a simulator that re-tints a sample interior as you move between kelvin values, useful for testing a paint scheme. It is a simulation rather than a measurement, but it is a useful starting point for comparing the overall effect of warm and cool light on an interior.