The dress was a 2015 online viral phenomenon centred on a photograph of a dress. Viewers disagreed on whether the dress was blue and black, or white and gold. The phenomenon revealed differences in human colour perception and became the subject of scientific investigations into neuroscience and vision science. The phenomenon originated in a photograph of a dress posted on the social networking service Facebook. The dress was black and blue, but the conditions of the photograph caused many to perceive it as white and gold, creating debate. Within a week, more than ten million tweets had mentioned the dress. The retailer of the dress, Roman Originals, reported a surge in sales and produced a one-off version in white and gold sold for charity.