On February 26, 2015, a Scottish musician posted a photo of a dress on social networking site Tumblr.
Within 24 hours, the £50 two-toned garment – made by British retailer Roman Originals – had become a worldwide internet sensation.
Millions of social media commentators were divided on its true colors – was it gold and white or black and blue?
Celebrities including Kanye West, Justin Bieber and Taylor Swift even waded in on the viral phenomenon, dubbed ‘The Dress That Broke the Internet’.
Now, 10 years later, the British sensation is still stirring fresh debate, with many social media users still fighting their corner.
‘On 26th February 2015, the world disagreed over whether the item of clothing was black and blue or white and gold,’ says Roman Originals.
‘The phenomenon revealed differences in human colour perception which have been the subject of ongoing scientific investigation.’
Here’s how the simple optical illusion divided the world – and the mind-boggling tricks that have baffled us ever since.
It is the question that has divided the internet for 10 years: is this dress white and gold, or blue and black?
In early February 2015, The Dress was on sale at Cheshire Oaks Designer Outlet near Chester when it was snapped by Cecilia Bleasdale, a social worker living in Lancashire.
Cecilia purchased it to wear at the upcoming wedding of her daughter, Grace, and sent a photo of it to her.
Grace – who perceived it in the photo as white with gold lace – was shocked her mum had chosen such a light colour.
When Grace posted the snap to Facebook on February 7 asking for a verdict, a disagreement erupted over the colour of the outfit.
After the wedding, guest Caitlin McNeill, a 21-year-old musician from Scotland, remained fascinated by the photograph.
On February 26, she posted the photo to her blog on Tumblr, and inadvertently launched the debate into the online stratosphere.
It went viral with around 5,000 notes – a remarkably high number for Tumblr – and caught the attention of Buzzfeed, Washington Post and US magazine Wired.
By the following day, #TheDress, #TheDressIsWhiteAndGold and #TheDressBlueAndBlack were among the top trending hashtags on Twitter.
The Dress was made by British clothing company Roman Originals, which offers ‘affordable women’s clothing and designer ladies fashion’
Among the celebs to give their verdict were Kim Kardashian and husband Kanye West, Justin Bieber, Katy Perry and Will Smith’s son Jaden
The following month Taylor Swift posted: ‘I don’t understand this odd dress debate and I feel like it’s a trick somehow.I’m confused and scared.PS it’s OBVIOUSLY BLUE AND BLACK’
Among the celebs to give their verdicts were Kim Kardashian and then-husband Kanye West, Justin Bieber, Katy Perry and Will Smith’s son Jaden.
Justin Bieber posted: ‘And for everyone asking I see blue and black’, while Kardashian said: ‘I see white & gold. Kanye sees black & blue, who is color blind?’
Actress Mindy Kaling also joined the discussion, writing on Twitter: ‘IT’S A BLUE AND BLACK DRESS! ARE YOU F***ING KIDDING ME.’
The following month Taylor Swift posted: ‘I don’t understand this odd dress debate and I feel like it’s a trick somehow.I’m confused and scared.PS it’s OBVIOUSLY BLUE AND BLACK.’
Grace and her new husband Keir Johnston – now in jail for a shocking campaign of domestic abuse – even appeared on the Ellen DeGeneres show.
Roman Originals later auctioned off a white and gold version for charity, and said it received 3,622,960 visitors to its website in 48 hours.
As promo images show, the dress is unequivocally blue and black, but the photo itself became one of the most famous optical illusions of all.
There is no scientific consensus on why some see blue and black while others see white and gold, but we know that there are individual differences in how we perceive colour.
Circulating on Twitter 10 years ago was this image, showing how the original photo (left) contrasts with manipulated versions
And these personal perception differences are exacerbated by the famous photo’s low quality and poor lighting.
Claiming to finally give an answer, a 2017 study concluded that our internal body clocks – and whether we get up early or get up late – may dictate what we see.
Early risers who spend their day in sunlight are more likely to see white and gold, while night owls whose world is illuminated by artificial light will see black and blue.
‘If illumination conditions are unclear, your assumptions about the illumination source will matter,’ said author Pascal Wallisch, a neuroscientist at New York University.
‘Shadows are blue, so we mentally subtract the blue light in order to view the image, which then appears in bright colours – gold and white.
‘However, artificial light tends to be yellowish, so if we see it brightened in this fashion we factor out this colour – leaving us with a dress that we see as black and blue.
‘This is a basic cognitive function – to appreciate the colour on an object, the illumination source has to be taken into account, which the brain does continuously.’
Dr Paul Knox, formerly at the University of Liverpool’s Department of Eye and Vision Science, said ‘colour isn’t something that exists in the world’.
Twitter user Hope Taylor used Adobe Colour to highlight different shades in the original photograph
This illustration shows two ways in which the photo may be perceived: blue and black under a yellow-tinted illumination (left) or white and gold under a blue-tinted illumination (right)
‘Different wavelengths of light exist and can be observed but colour is something we make up inside our heads,’ he said.
‘What meets the eye is light at given wavelengths that then stimulates several distinct pathways that process these different wavelengths.’
Exactly what the brain interprets may also be complicated by factors like the device you’re viewing the photo on, the lighting in which you’re viewing the photo and your own expectations.
In the decade since The Dress took over social media, mind-boggling visual tricks have continued to fascinate, astound and infuriate us.
A pair of trainers posted by Facebook user Nicole Coulthard divided the internet in a similar way a couple of years later, having caused a ‘big argument’ with her mum.
Some people saw pink trainers with white laces, while others saw grey trainers with blue laces.
In 2016, BBC presenter Marc Blank-Settle posted a uncanny clip of toy wooden train tracks that look different sizes – but were actually the same.
The so-called Jastrow illusion makes two identical curved shapes appear different, because the brain compares two sides that are next to each other.
Facebook user Nicole Coulthard shared a picture of her friend’s new shoes, asking people what colour they thought they were – blue and grey or white and pink
And in 2021, a strange illusion showing parallel bars with different shades of purple created a new viral debate on Twitter.
People couldn’t agree on how many bars there were in the image, due to the Mach Bands illusion, named after an Austrian physicist.
Different people will see different amounts of shades of the lines based on cones in their eyes, or even how much light is in their surrounding environment.
One of the more recent illusions is the photo showing a plate of strawberries that doesn’t actually have any red in it, despite what our brain tells us.
The image has a cyan filter that renders the strawberries completely grey, but our brains interpret the fruit as red due to our past knowledge.
Meanwhile, the ‘expanding hole’ illusion tricks the brain into thinking a static black hole is expanding, as if we were moving into a dark tunnel.
It was recently created by by Professor Akiyoshi Kitaoka, a psychologist at Ritsumeikan University in Kobe, Japan.
Experts stress that there might not be a definitive answer to these illusions, meaning the debate over who is right and who is wrong often pointless.
Dr Dean Jackson, a biologist and BBC presenter, has shared a strange illusion on TikTok, which tricks your brain into thinking strawberries are red
Four years ago, Twitter users hotly debated how many different shades the image shows, with some seeing 11 and 14 and one user even saying they can see 17 shades
Have a look at this image. Do you perceive that the central black hole is expanding, as if you’re moving into a dark environment, or falling into a hole? The ‘expanding hole’ is an illusion new to science, researchers say
Different people will see different amounts of shades based on ‘cones’ – light-sensing cells in the retina – or even how much light is in their surrounding environment.
In people with a colour impairment or colour blindness, some types of cones are missing or inactive.
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That means there will be regions of the visible light spectrum that your eyes are unable to register, making it harder to perceive the difference between similar shades.
‘Even though all humans see more or less the same range of the electromagnetic spectrum that is visible light for us, there are still individual differences,’ Dr Michael J. Proulx, a neuroscientist at the University of Bath, told .
‘Average vision is trichromatic – we have three types of cone cells in the eye that combine to allow us to see the colours we see.
‘In colour-blindness there is dichromacy, where only two types of cone cells are available, and so the ability to see colour is reduced, and this more common in males.
‘There is even tetrachromacy where there are more than three cone cell types so even more colours can be seen, and this is more common in females.
‘Besides those large differences, every person’s eyes have different optics that screen the incoming light in different ways, and different densities in pigment in the eye that impacts light absorption.’