Su, Zhang, Zhu, and Xia found that “Gradient colours are widely used in product design. The variation of gradient colours muting a colour as a series of steps from bright to dull creates a soft and gradual impression while also affecting people’s perceptions. . . . In the case of controlling for aesthetic differences, [this] study manipulated two types of colour gradients (dark colours fading upward from the bottom versus downward from the top) and measured the perceptions of product…