Pigment Lab
Mix the colours of autumn
A leaf's autumn colour is just a handful of pigments competing for the light. Slide them, add weather, and watch the colour change — then turn whatever you make into a shareable palette.
Your palette
Tap a swatch to copy its hex code.
Saved palettes
The four pigments
Chlorophyll masks everything while it lasts. As it fades, the others show through.
Weather effects
Autumn is a weather story. Turn conditions on to see what they do — and read why underneath.
Species presets
Jump to a recipe that mimics a real tree's typical autumn colour.
The science
Why leaves change colour
Two things happen at once: the green fades, and reds may be actively built. Here is what each pigment is doing.
What makes a good year
Sunny days + cool nights
Bright days let the leaf make lots of sugar; cool nights above freezing trap it, driving anthocyanin production. This is the recipe for brilliant reds.
An early hard frost
Freezing damages the leaf's chemistry and can cut the red show short, leaving dull brown. A gentle frost is fine; a hard one ends the party.
Summer drought
Stress can make trees shut down early, so colour arrives sooner but with more brown and less red. Heavy rain and wind strip leaves before their time.
Day length sets the clock
Shortening days trigger the change, but temperature, sunlight and rainfall decide how bright and how long the display lasts. That is why every autumn is different.