What Does Red and Blue Make? Mixing Paint, Light and Purple

Red and blue make purple. That's the simple answer, and it's what most of us learned at school with a paintbox. But if you've ever mixed red and blue paint and ended up with a muddy brown instead of a clean violet, you'll know there's more to it. And if you mix red and blue light rather than paint, you won't get purple at all.

In this guide I'll explain what red and blue make in paint and in light, why your purple sometimes turns out brown, how to mix lighter, darker, warmer and cooler purples, the names of the different shades of purple, and how to use purple beautifully in your home.

What Do Red and Blue Make?

Red and Blue Paint: Why They Make Purple

Artists traditionally use the RYB colour wheel, built on three primary colours: red, yellow and blue. Mixing two primaries gives you a secondary colour:

• Red and yellow make orange
• Yellow and blue make green
• Red and blue make purple

Purple sits between red and blue on the colour wheel, so the more red you add, the warmer and pinker your purple becomes, and the more blue you add, the cooler and deeper it becomes.

The RYB wheel is a practical tool for painters rather than a precise scientific model. Colour scientists describe pigment mixing with a different set of primaries, cyan, magenta and yellow, which is why printers use CMY inks. The RMIT University overview of additive and subtractive colour explains that the subtractive primaries are cyan, magenta and yellow, and that the RYB wheel is still used in visual arts to teach colour mixing.

Why Does Red and Blue Sometimes Make Brown?

This is the most common frustration. The reason is hidden yellow.

Many red paints lean warm, towards orange, which means they contain a little yellow. Many blue paints lean towards green, which also means a touch of yellow. When you mix them, that yellow meets the purple you're creating. Yellow is purple's complementary colour, opposite it on the colour wheel, and complementary colours neutralise each other. The result is a dull, grayish or brownish purple.

How to mix a clean purple:

Ultramarine blue with a crimson or magenta red gives a much brighter, cleaner purple than an orange-red with a green-blue.

Red and Blue Light: Why They Make Magenta

Light works the opposite way to paint. Screens, stage lights and LEDs mix colour additively, adding light together, and their primaries are red, green and blue (RGB). Mix red and blue light and you get magenta, a bright pinkish purple. Mix all three at full strength and you get white.

That's why the same two colour names give different answers: red and blue paint make purple, but red and blue light make magenta.

How to Mix Different Shades of Purple

Tip: always add the darker colour to the lighter one in small amounts. It's much easier to darken a mix than to lighten it again.

The Many Shades of Purple

A Little Colour History

Purple has a long association with wealth and power. In the ancient world, the most famous purple dye, Tyrian purple, came from sea snails and was so costly that it became a symbol of royalty. Purple only became affordable in 1856, when a young chemist, William Perkin, accidentally created mauveine, one of the first synthetic dyes, and started a fashion for mauve.

How to Use Purple at Home

Deep plum and aubergine

Plum walls make a living room or snug feel rich, warm and cocooning, especially with velvet, brass and green plants. Blush pink upholstery softens the depth beautifully.

Soft lilac and lavender

Pale purples are calm and restful, ideal for bedrooms and bathrooms. Pair them with white, natural wood, rattan and soft green.

Purple accents

If you're not ready for purple walls, start with velvet chairs, cushions, artwork or a painted door. Purple velvet looks especially luxurious with navy, brass and warm wood.

Colors that go with purple

Purple and green are especially lovely together, as are pink and green; there are plenty of pink and green room ideas that work just as well with lilac or mauve. If you're building a whole scheme, choosing the right color palette step by step makes it easier.

Frequently Asked Questions

What color does red and blue make?

Red and blue paint make purple. Red and blue light make magenta.

Why did my red and blue make brown?

Your red or blue probably contained some yellow. Yellow is purple's complementary colour, so it dulls the mix towards brown or gray. Use a cool, pinkish red and ultramarine blue for a cleaner purple.

What do red and blue make in light?

Magenta. Light mixes additively, so red and blue light combine to make a bright pinkish purple.

How do you make light purple?

Mix red and blue to make purple, then add white. Add a little more blue for lavender, or a little more red for lilac.

How do you make dark purple?

Add more blue than red, then a small amount of black or brown. Plum and aubergine are both dark purples.

Is purple a primary color?

No. In traditional colour mixing, purple is a secondary colour, made from the primaries red and blue.

What color do red, yellow and blue make together?

Mixing all three primaries in paint makes a dark brown or muddy gray, depending on the proportions.

Red, Blue and Everything in Between

Red and blue make purple in paint and magenta in light, and the exact shade you get depends on which red and which blue you choose. Pick a cool red and a warm blue for a clean violet, add white for lilac and lavender, and add black or brown for plum and aubergine.

And if you'd love to bring purple into your home but aren't sure where to start, you can book a one-hour online interior design consultation with me.