Blue and black, or white and gold?
The photo that split the internet, and why you and your friends saw different colours.
How this site works. Every fact is in our own words and linked to its source, beside it. Where good sources disagree, we show each version in a “Sources differ” box. Every picture is our own drawing: we don’t copy the famous originals, we make our own versions of the idea.
What happened
In February 2015 one photo split the internet: was the dress blue with black lace, or white with gold lace? WIRED
Michael Bach calls it a social illusion: it only gets interesting when you compare notes with other people. Michael Bach
It has nothing to do with colour blindness. Michael Bach
Your brain guesses the light
The colour of a non-glowing thing like a dress depends on two things: the colour of the light falling on it, and how its material reflects each colour of light. Michael Bach
Your visual system tries to work out the colour of the light and ‘subtract’ it. This is called colour constancy, and it usually works well. Michael Bach
That is why a photo taken on a glacier at noon can look surprisingly blue when you look at it at home. Michael Bach
Daylight itself changes colour, from pinkish red at dawn to blue-white at noon and back to reddish at twilight. WIRED
Conway, of Wellesley College, suggested that people discount either the blue end or the gold end of daylight’s colours, and so see white and gold or blue and black. WIRED
Conway joked that night owls might be more likely to see blue and black. WIRED
A difficult photo
Bach blames a poor photo: badly lit, overexposed on one side and showing only the dress, so the brain has too little to go on when it guesses the light. Michael Bach
Colour names play a part too: a bright, bluish colour counts as ‘white’ for some people and ‘blue’ for others. Michael Bach
Look at two stripes through small holes, cut off from the rest of the picture, and the argument mostly goes away: both sides tend to see brownish and light bluish. Michael Bach
Pixels that some people saw as gold measured R 93, G 76, B 50: on their own, a kind of orange. WIRED
It has been called the ‘Necker cube of colour vision’: two readings are about equally likely, but unlike the Necker cube it is hard to flip between them yourself. Michael Bach
Jay Neitz, who saw white and gold, said that in 30 years of studying colour vision it was one of the biggest individual differences he had ever seen. WIRED
So what colour is it?
The real colours: sources differ
- Bach’s answer to the real colours, well lit with white light: black and blue. Michael Bach
- WIRED’s verdict in 2015: the dress is blue. WIRED
- Neuroscientist Bevil Conway ran the pixels through Photoshop and decided the dress was actually blue and orange. WIRED
Bach and WIRED agree on blue. Conway’s “blue and orange” comes from measuring pixels in the photo, not from looking at the dress itself.
Our view: the dress is the best argument ever made for asking “what do you see?” before saying “you’re wrong”.