The science behind the dress colour illusion Internet The Guardian Plus Size Light Blue Wedding Guest Dress Dia & Co The actual dress was black and blue. The confusion came from how lighting and color perception tricked people's brains, making some see it as white and gold. It became a viral example 10 years ago, a simple photograph of a dress sparked a global debate unlike anything seen online before. Posted in 2015, the image caused people to argue intensely over whether the dress