The dress, which has gone viral on social media, has been in popular demand at the Horsham Roman Originals store in Swan Walk Shopping Centre.
The royal blue lace bodycon dress was first Tweeted by a Roman customer last week. It went around the world as people started to disagree about its colour.
Some people see it as blue and black while it appears white and gold to others.
Store manager Nicky Ferdinando said: “It’s our dress. We were crazy at the weekend. I work in the Staines branch as well and that one was crazy too. We had people coming in to have selfies with it.
“Our boss has been interviewed by the Washington Post. It’s 100 per cent Roman.
“It’s definitely blue and black. They are actually going to be making a gold and white one. We do it in cream and black as well.
“All day Saturday in Horsham people were having pictures taken. There were two guys who came in took a picture and said it was silver.”
“A lady in Scotland took the picture and put it on the social media sites and it went to the States overnight.
“It wasn’t done on purpose. It was a genuine customer who did it. It’s a lovely dress.”
Thousands of people were Tweeting it under the hashtag #TheDress and posting it on Facebook, international media were covering the story and celebrities worldwide were reposting the photo which has divided opinion.
There have been theories about it being different colours under different light, but scientists have explained it is the way the human brain processes colour.
The Horsham Roman branch is celebrating its first birthday in the town. It is a small Birmingham based family chain with 100 branches across the country.
Nicky said: “We’ve opened up quite a few in the south. All the stock is designed by us. It’s an unsung brand of the UK. We’ve got such loyal customers.”
Biology teacher and deputy head at The Millais School in Horsham explained the conundrum. She said: “Your brain compares backgrounds and ‘fills in the picture’.
“What we use in the background probably makes a difference to the colour that we then think we see. So ‘The dress’ is a ‘colour illusion’ where the object’s surrounding colours trick the eye into incorrectly interpreting the colour.
“Cells at the back of our eyes are light sensitive and help us tell the difference between colour and shade. There are two types – cones which detect colour and rods which only detect black and white. Cones come in three types – red, blue and green and we all have different ratios of them so this variation will also leads to different perceptions of colour.”
Lydia Graham, science teacher at The Weald School, Billingshurst, said: “The picture of the dress can look both black and blue or white and gold to different people at the same time. This is down to a phenomena called ‘colour constancy’, where the brain interprets the colours we see based on the surroundings we see them in.
“Our brain looks at the context we see the colours in to decide what it’s seeing! In the photograph of the dress, there isn’t much of a background to help, so each individual person’s brain is making a decision about how to interpret the colours.
“For some, that decision is black and blue and for others, white and gold.
“The lighting in the room we see it in also helps make this decision. Artificial, yellow light will help make the dress look lighter whereas bluer lighter will help make it appear darker.”