How Light Affects Paint Colour

29 May 2026

Colour is light. Without light, colour does not exist. Through the wavelengths, into the rods and cones in our eyes: colour — far from a static thumbnail or hue on a screen — is an ever-shifting, refracting form determined by our physiological interpretation of light.

With that, we’re going to discuss what this all means when choosing the right paint colour. We’re going to embrace the light and the shadows, amble through the north facing room to the south, learn what an incandescent lightbulb means and discover why knowing your Kelvins really matters.

“Light is therefore colour” — J. M. W. Turner

Colours on A Compass

Identifying Which Way your Room is Facing

North facing vs south; east or west? Where your room faces determines its colour. So, first, let’s figure out how to find which way your room faces.

There are two simple ways to find out:

1. Locate your house in Google Maps. If you’re on a desktop, the map is automatically pointing north. You can then figure out where the room is in relation to this. If you are on street view, the compass will appear on the right.

2. Walk into the room, get your phone out, tap on the Compass app. Aim your phone at the largest windows of the room. Whichever way the dial points, that is the orientation of your room.

Paint featured: Canopy Green

/cms/media/Untitled-design - 2026-05-28T154415.991.png

South-Facing Rooms

Have the most light of all four orientations.
Light is most intense at midday, stretching from dawn until dusk
Filled with warm light in good weather
If you live in the Southern Hemisphere, the north and south characteristics are flipped around

Sanderson's Advice:

A jack of all trades, the south-facing room is perhaps the interior designer’s most beloved. You can play fast and loose with colour, and cast your heuristic net wide, since it’s hard for pigments to feel cold.

What you need to know is that colours will always feel warmer and brighter in a south-facing room. So, ochres and lemons will be galvanised by the sun’s overtones — this may be overly dazzling for some but perfection for others. A south-facing room is like an effortless surge of intensity. Everything is more intense; colour is more saturated. Will you cool down with neutrals and blues, or up the ante by earthen russets and greens?

Paint featured: Bastille

North-Facing Rooms

Has the least amount of light of all four orientations
Has a propensity for a ‘greyness’ of light, especially if the weather is overcast

“Were it not for shadows, there would be no beauty.” ― Jun'ichirō Tanizaki

Sanderson's Advice:

Unfairly seen as the south’s shadowy, ice-cool sister, the north-facing room sings with potential, just in different notes. The shadows are softer, the atmosphere is calmer, the stakes are lower. Instead of seeing north-facing rooms like a rose that refuses to grow, see it instead like a shade-loving fern. Tend to it correctly and watch it flourish.

Work with your shadows. Find the colours that have richness and depth. Strike out greys, cold blues and whites, but bring in the browns, deep reds, the ochres and wood tones. Don’t forget to think about the ‘fifth wall’; this is a perfect opportunity to colour drench your room, from ceiling to wall.

Paint featured: Driftwood Grey Light

/cms/media/SDG Sanderson Salvesen Graham June 2023_36-1.jpg

EAST-Facing Rooms

Bright light in the morning
Cool in the afternoon

Sanderson's Advice:

If north and south are each other’s opposites, then east and west work in a kind of ‘same but different’ doppelgänger dance. If you wake up in an east facing room, light will stream through to bathe your space beautifully each morning.

When choosing a colour for an east-facing room, you need to consider what you will be doing in the space and when you will be there. Light to mid-tone colours can feel like a lovely constant, with green being a particularly great choice.

Paint featured: Botanical Green

/cms/media/Untitled-design - 2026-05-28T154433.846.png

WEST-Facing Rooms

Cool in the morning
Bright light in the afternoon

Sanderson's Advice:

Just as with an east facing room, you’re looking for colours that can hold their nerve across dramatic changes in light through the day. You may wake up in the shadows, while intense light arrives at golden hour.

Paint featured: Ming Gold

introduction to artificial light

Different light bulbs cast different tones, and each one will alter how a colour is read. Some will warm it; some will sharpen it. One failsafe piece of advice is to have your lightbulbs for the room before you buy your paint test pots. The colour will look distinctly different under contrasting lighting conditions.

Behind all of this sits a useful measure, Kelvin (often written as K). Light temperature is not about heat, but about the colour of the light itself. It describes whether a light appears warm and golden or cool and blue. Warm light, around 2700 to 3000K, appears soft and yellow-toned neutral light, around 3500 to 4100K, is more balanced and closer to daylight. Cool light, 5000K and above, is crisp, blue-toned, and more clinical in feel. You can use a Kelvin app to measure the light temperature in your room, and the score will be on the packaging label of any lightbulb sold.

/cms/media/Untitled-design - 2026-05-28T154426.377.png

When it comes to artificial light, there are three general groupings:

Incandescent light bulbs

A soft, warm glow, these amplify tones, soften paint colours, and lend a gentle, rounded quality to a room. Best for living rooms, bathrooms, and bedrooms.

Fluorescent light bulbs

Cool and sharp, blues and greens become more saturated, and brighter colours can feel more intense. Best for places of focus, like offices or utility rooms.

Halogen lighting

A middle ground. Brighter and closer to white light, it renders colour more accurately and blends more easily with natural daylight. This can work well for kitchens.

Paint featured: Blue Clay

feeling inspired?

With a quintessentially British feel, Sanderson Paint is available in over 150 colours and a choice of two finishes ― Active Emulsion and Water-Based Eggshell. Discover which shade looks best in your home.