How do you choose interior paint colours?

Start with the light in the room, not the colour chart

Light decides how a paint colour looks, so check the room's light before you look at a single swatch. Dulux says the amount of natural and artificial light coming in changes how a colour appears. Taubmans gives the same first step: before you go to the shop, think about how much natural light the space gets, because that helps decide the right shade.

Which way does the room face? Haymes Paint, an Australian paint maker, says north-facing rooms have a lot more warmth and brighter light, while south-facing rooms look cooler and darker and may need more artificial lighting. Watch out for advice written for the northern hemisphere. It flips north and south, so a tip from an overseas site can point you the wrong way in an Australian home.

Warm or cool? Dulux says warm whites have undertones of yellow, pink or orange and add softness. Cool undertones have hints of blue, purple or green and suit open-plan rooms with plenty of natural light. If a room's flooded with light, Dulux says cooler colours may suit. If it needs lifting, a warmer tone can help brighten it.

Your lights, floors and furniture. Dulux says ceiling lights and lamps change the tone too. It also says furniture and materials like timber or concrete reflect the colours around them. So test against your own floorboards and sofa, not a white card in the shop.

LRV tells you how light a colour really is

Light reflectance value, or LRV, is a number from 0 to 100 that tells you how much light a colour bounces back into the room. Taubmans describes LRV as a value from 0 to 100. Dulux prints it as "Light Reflection Value" on each colour's page, so you can compare two colours by number instead of by eye under shop lights.

Here's how a handful of Dulux colours compare, straight from their colour pages. The higher the number, the more light the colour reflects. Dulux calls Lexicon, at 84, great for light reflectance.

How to use it. Dulux says south-facing rooms in the southern hemisphere get less sun and cooler light, and suggests deeper, warmer colours there. LRV isn't a rule, though. Two colours with close numbers can still look different because of their undertones, which is why you still test.

Pick three colours together: walls, trims and ceiling

Choose the wall, trim and ceiling colours as one scheme, not one at a time. A trim white that looks fine on its own can look grubby next to a crisp wall, or too stark next to a warm one. Dulux sorts schemes into three kinds:

• Monochromatic. Shades of one colour. Dulux says these feel serene and relaxing, with light tones feeling delicate and dark tones moody and dramatic.
• Harmonious. Colours that sit next to each other on the colour wheel. Dulux says these are comfortable but have more energy than a one-colour scheme, which suits people who want to play with colour without going bold.
• Contrasting. A bold or deep colour from one family with a lighter colour from another. Dulux says the result can be quite striking.

A shortcut: Dulux's triple colour chips show one colour at different strengths. Dulux suggests the top or middle shade for a feature wall and the bottom one for the main walls or trim through the rest of the room.

Trims. Haymes says white or a light colour on skirting, architraves, doors and windows makes a room feel more spacious. Our guide to painting doors, skirting and frames covers the paint side of that.

Ceilings. Ceilings don't have to be white. Dulux says to weigh up the whole scheme and the room size first, and that a bigger room can carry more colour. In a very small room, Haymes says you can run the wall colour right up onto the ceiling to make it look bigger. Once you've got the colours, pick the sheen with our guide to interior paint finishes.

Test sample pots for at least three days before you buy

Sample pots show the real paint in your real light, so they're the test to do before you buy. Haymes says this step matters most if you're thinking about a bold colour or something very different from what's on the walls now. Here's a testing routine pulled from four paint makers that sell in Australia.

1. Shortlist first. Haymes suggests narrowing whites down to three or so before you buy pots, and the same trick works for any colour. Dulux's in-store colour walls run warm colours on the left, cool on the right and brighter colours at the top, which helps you find your corner fast.
2. Buy the right sample. Wattyl sells 500ml samplers in four depths, from White for very pale shades to Strong for navy, terracotta or charcoal.
3. Paint a board or the wall. Wattyl says to put two coats on an A4 board or straight onto the wall. Haymes suggests card, and Taubmans says a piece of white paper works if you don't want to paint the wall.
4. Move it around. Wattyl says to move the board around the room as the light changes. Dulux suggests checking it behind the sofa, near the kitchen cabinets and against your artwork.
5. Look morning, afternoon and night. Dulux says to test at different times of day and under artificial light at night.
6. Wait three days. Dulux recommends leaving samples up for at least three days before you decide.
7. Check whites against paper. Haymes says holding a white next to plain white paper shows up undertones you might have missed.

Going lighter over a dark colour? Dulux says prep and undercoat can be an important step to get an accurate colour, especially over darker colours or bare surfaces. So a sample painted straight over the old dark colour may not show the true result.

Room by room starting points from the paint makers

Each room has its own light and job, so start each one from a different place. None of these is the one right answer for every home. They're starting points to shortlist from, then test.

Dulux also says cooler colours seem to step back and make a space look bigger, while warmer colours draw attention. Keep that in mind for a narrow hallway or a feature wall you want people to notice.

Sage green, blue and red: how the popular families behave

Sage green, blue and red behave very differently on a wall, so match the family to the room's light and use. Here's what the paint makers say about each.

Sage green. Wattyl calls green a top trend, from sage to avocado, and lists Sage among its top picks. Dulux says lighter muted greens add a peaceful, relaxed feel, while citrus and lime greens liven a room up. It also calls greens versatile and easy to live with. Greens run from yellow-leaning to blue-leaning, so check which way your sage leans against your floors.

Blue. Wattyl suggests soft blues in bedrooms and deep navies for accent walls. Blue sits on the cool side, so it can feel calm in a bright room and a bit cold in a dim south-facing one. That's the kind of thing a three-day sample will show you.

Red. Dulux puts reds with the warm colours that add vibrance and draw attention, so think about red for a feature wall before you commit a whole room. Wattyl lists Heritage Red among its heritage picks for Federation and country-style homes. Haymes' advice on bold colours holds here too: paint a sample patch first, so you can see how it looks through the day and at night.

Picking colours to get the house ready for sale photos? Our guide to painting before selling covers timing and which rooms to do first. For the outside, see choosing exterior house colours.

When to bring in a painter

Bring in a licensed painter once the job is bigger than a weekend, or once you want the colours you picked to come out even across every wall. In Queensland, the QBCC says a licence is mandatory for painting work worth more than $3,300. Under that, a licence isn't required, but the QBCC urges people to use a licensed painter anyway because of how often painting defects get reported. You can check any painter on the QBCC licensee register.

We're QBCC licensed (licence 1281728) and we've painted Sunshine Coast homes since 1985. Our interior house painters quote after a free site visit, and we cover suburbs right across the Sunshine Coast, including Buderim and Noosa.

Doing it yourself? Our step by step guide on how to paint a room picks up where this one ends. For a ballpark before you call anyone, see what interior painting costs.