The Sun, 11 October 2017
The Sun covered a story of Facebook user, Nicole Coulthard, after she shared a photo of a pair of shoes. Thousands of people commented on the snap, debating their true colour. Daniel Hardiman-McCartney, Clinical Adviser at the College of Optometrists explains:
“The reason for the debate is down to how the brain processes colour. The visual system corrects our perception of the colours seen based on what it know about the colour bias of the light shining on the subject, in this case a pair of shoes. This effect is known as ‘colour constancy’ it is a kind of clever colour correction constantly being applied to what we see. Where there is ambiguity in the nature of the light source our visual system has to guess, that is why you get different opinions.
“In the case of the shoes, are they turquoise and grey, or pink and white? The brain is guessing was it a warm yellow light like a candle or a blue white light from a flash, and compensating accordingly. The colour of the hand, adds to the confusion, the visual system maybe using the skin as a reference tone to adjust. This effect is similar to that observed by the infamous ‘The dress’ image seen from 2015. Colour constancy confusion, due to ambiguity about the source light. This illusion appears less divisive than the dress, of which there has since been much scientific discussion.
“When looking at a person wearing white during a sunset, the brain adjusts for the sun lights’ bias towards yellow. In order to perceive the outfit as white, your brain adds extra blue tones. When the same white outfit, is viewed indoors under a shops fluorescent light, the brain makes a different adjustment to add extra yellow ensure the outfit remains white. This variation helps us see colours consistently regardless of the surrounding light.
Read more about the dress colour illusion.