Eye Health

Updated 27 February 2015

Why can nobody agree on the colour of THAT dress?

How is it that people can see the same thing as being either white and gold or blue and black?


The internet is being broken by a dress. Not because of who's wearing it (indeed, nobody is), but because of what colour it is.  

People see the dress below as being either white and gold, or blue and black. At the time of writing, a Buzzfeed poll has it as 72% in the white-gold camp, with 28% calling blue-black. Over 1.5 million have answered the poll, indicating the scale of the issue. Channel 24 has the best of the MASSIVE reaction here.

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So how is it that this can happen? Science, that's how.

The colour people see isn't absolute. While it isn't a case of "there's no wrong answer," and there is an absolute colour to the dress (though how people experience, that colour could vary wildly, but that's a different conversation), the way different people process the image is to blame. 

As light comes into your eye it activates a large number of cells. These are split between rods, which identify light and dark, and cones which pick up colour. These then send this information, in the form of simple impulses, along the optic nerve to the occipital lobe which is right at the back of your brain and is responsible for visual processing, as Wired described in their lengthy interpretation. 

A number of different reasons have been suggested for why this dress is so polarising. Some have suggested that it's due to the ratio of the various types of cones in your eyes. Cones pick up either red, green or blue light but, surprisingly, you don't have equal numbers of each. In fact, the ratio can vary quite drastically from person to person. It could be the case that people with more blue-receptive cones could be picking up more blue light and thus seeing it the white, which is the most reflective colour, as blue. In turn, the brain applies this colour mix to the other bands of the dress and interprets it as black. 

However, if this were the case then people might not agree on many colours at all and the internet would be full of arguments that the sky is actually gold, which, thank goodness, it isn't.

Instead, the difference is due to what your brain thinks it's going to see. This could be because of what you looked at before you saw the image or perhaps if you've seen similar patterned dresses before which you interpreted as white and gold. It could even be as simple as if someone tells you that the dress is white and gold before you look at it. It's also unlikely that once you see it you'll be able to change from a white-gold seer to a blue-black one, though not impossible. For what it's worth, I see it as white and gold, but if I see without expecting it, such as on somebody else's computer screen, it appears blue and black but fades into white and gold after a few moments.

This highlights a key factor of all human senses which is that the brain has a much bigger effect on how we sense things than the actual senses themselves. It's the same reason people who have experienced a traumatic experience can go blind despite any actual damage to their visual apparatus. 

The problem with this particular dress is that, due to the light it was taken in, amongst other factors, it sits right on a perceptual boundary and as such it's very easy for your brain to pick it up as one of two distinct colours. A big part of this whole argument is that it's a poorly, weirdly taken photo which has allowed in more blue light than it should in comparison to the other colours. This can also be proved with another picture from Amazon, seen below.

So, what colour is is actually?

It's blue. Don't believe me? We ran the picture through photoshop, and the colour code for the white or blue part of the dress is #8292b4, described by ColorHexa as "slightly desaturated blue" and the gold is #7d6c41 which is a kind of goldy-orange.

Want more proof? In the image below, square A and square B are the exact same colour (#787878). Your brain sees that this block is lighter than the blocks around it and presumes that it is probably lighter than average. Then, seeing that there is a shadow, it presumes that it would be lighter still and counteracts this by increasing the lightness of its interpretation of the block.

Some specialists, however, disagree that the dress is blue. pointing to a condition called achromotopsia as the likely cause. The opthalmology department at Tygerberg hospital had this to say

"I, Prof Meyer, HOD ophthalmology department Tygerberg and one of our senior registrars, Dr A Haarhofd had a look at the image with a red filter, green filter and a neutral density filter. The red filter blocks out green light, the green filter blocks out red light and the neutral density filter adjusts the contrast.

We found that the colour filters had the largest effect on the change of colour. And the one affecting contrast did not.

It's most probable that those seeing it black and blue have some degree of achromatopsia (colour blindness) or have deutranopia (green colour vision deficiency or deutranopia (red colour vision deficiency).

It's also possible that the computer screen or viewing devices settings differ.

Please remember no two people see colour the same way."

Our optometrist, Megan Goodman, had a slightly different theory, although she also pointed out that achromotopsia could be an issue. 

"The colour discrepancy could most likely be caused by contrast abnormalities, caused by anything as mild as cataract formation to changes occurring at the optic nerve.

Another cause could be colour vision achromatopsia (anomalies) which can be from birth or acquired."

To even further complicate the issue, according to a landmark paper published by Jules Francois in 1962, achromotopsia affects less than 1% of people. 

The debate, and hysteria, continues.


Related links

Eye problems? Ask our optometrist a question 

Are you colour blind?


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Megan Goodman qualified as an optometrist from the University of Johannesburg and is currently practising at Tygerberg Academic Hospital in Cape Town. She has recently completed a Masters degree in Clinical Epidemiology at Stellenbosch University. She has a keen interest in ocular pathology and evidence based medicine as well as contact lenses.

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