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Optical illusions have been blowing the minds of the internet for a while now and the latest illusion to surface is no different. At first glance this photo of a group of teens looks to be in full colour, right? Wrong.

This black and white image is using a ‘colour assimilation grid illusion’ which has tricked our brains into thinking that it’s in full colour. This effect has been made by laying a grid of coloured lines over the original black-and-white image. You can have a go at making your own 3D illusions using our helpful step-by-step guide.

If you look at this photo from a distance, you wouldn’t even know it was black and white.

Optical scientist Bart Anderson told ScienceAlert “The colour system is what vision scientists refer to as ‘low pass’, i.e., many of the receptive fields that code colour are quite large. The grids get ‘averaged’ with the achromatic background, which then gets attributed to that part of the image.” And as one Twitter user calculated, 36% of this photo is actually coloured, so technically our brains are just filling in the gaps, making the photo look coloured.

Digital media artist and software developer Øyvind Kolås is the man behind the illusion. Kolås has experimented with a number of different overlay textures to see what would work best. The artist was able to create a similar but less effective illusion with dots, stripes and also words.

Kolås’ optical illusion using different coloured dots. (Image credit: Manuel Schmalsteig / Øyvind Kolås)

We aren’t the only ones feeling completely mesmerised by these illusions — the internet is also totally baffled, with users taking to Twitter to express their confusion. One user even had a go at making their own colour grid assimilation illusion.

Excerpted from https://www.creativebloq.com/news/monochrome-to-colour-illusion