What a lovely time of year—when the leaves of deciduous trees in many forests change from the deep greens of summer to the yellows, oranges and reds of autumn. But what makes the leaves change colour, and what compounds are responsible for nature's spectacular display?

Many of us will know the green of chlorophyll, but leaves also contain carotenoids. As the chlorophyll fades, the golden oranges of these carotenoids start to shine through. You may recognize one carotenoid, beta-carotene, from carrots.

Another carotenoid, xanthophyll, is responsible for the beautiful bright yellows.

The leaves of some trees also produce anthocyanin as autumn begins, which produces those beautiful deep reds.

This sketch features in my book Big Ideas Little Pictures

Autumn leaves and the compounds that cause their colours

A cheeseboard is a highlight of the holidays for me. Here are some simple guidelines on how to create a winning one that looks and tastes the part.

I think the key really is the range of textures in the cheese. If you’ve got a hard, semi-hard, and soft cheese you’re onto a good start. If you can add in a crumbly and creamy and make sure you have a range of strengths from mild to mature, stinky or blue you’re onto a winner. Then make it amazing by adding complements from the sweet and salty buckets and don’t forget the crackers and breads.

If you want show off, try to cover a range of cheese shapes, colours and milks such as goats and sheep as well.

And because you may find yourself curious about it: origins of Boxing Day

Compose a cheeseboard

The effect you may have noticed where things further in the distance lose their intensity and colour until they fade into the sky. Most often noticeable with hills or mountains, but also in a misty forest as mist, dust, fog or things like pollution increase the effect.

If it’s a blue sky day, the distance will take on a bluer tone like the colour of the sky.

This scene painted from our ascent of Mt Rainier in the Pacific Northwest. And here’s a sunset version.

Atmospheric perspective

The 60-30-10 color rule is a handy and memorable technique for a great start in simple branding. 

Think of a suit where about 60% of the colour you see is the suit, 30% the shirt and 10% accent or highlight with the tie. Classic.

Also see: The basic colour wheel other drawing sketchplanations

60-30-10 Colour rule

With primary colours - red, blue and yellow - secondary colours, made by mixing the primaries - orange, purple and green - and complementary colours - from the opposites on the colour wheel - red and green, blue and orange, yellow and purple.

It’s fair to say there’s a lot more to colour than this basic wheel. I will try to get back to it.

The basic colour wheel

The Stroop test is one of my favourite psychological tests. Definitely worth taking 2 mins right now to give it a go. Time yourself to say the colour of the word (not what the word says) for the first set. Then repeat for the second. Observe interference at work.

Colour sketches