Is this bag white or blue?

Social network users around the world are debating the true color of a bag that is photographed and posted on Twitter.

Taylor Corso posted a picture of American Kate Spade handbag on Twitter on October 4 and immediately received mixed comments about its color. Follow an online survey on the Telegraph with more than 10,000 votes, 95% of which say it is white, the remaining 5% see blue.

The bag has a controversial color.(Photo: Taylor Corso).

According to the Kate Spade maker catalog, the official colored bag is "mysterious green" (mystic blue) . It is also described as a lake-like color.

"Its true color is gray and blue, but I think that's not the color Kate Spade describes," the bag's owner said on October 5. She also explained on Twitter the true color of the bag but very few people believed her.

Last year, social network users also argued online about the color of a dress, with two lines of opinions saying it was white and black and blue.

Describe Kate Spade's bag.

David Williams, a scientist specializing in human eyesight at the University of Rochester, USA, offers the following explanation. He says light is made up of different wavelengths and the brain perceives them as colors. Light enters the retina, which is sensitive to light, activating sensitive cone cells with red, green or blue wavelengths. However, the wavelength that your eyes detect may not be the wavelength of the object you are looking at.

Williams thinks that each person's brain may have different assumptions about how the object is illuminated . So, if each person's brain assumes light reaches the object in different ways, it will decode into different colors.