scarlet letters on a white background are good. According to the inquiry, official website of Guangwang shows that red is positive, healthy and warm. As a symbol of excitement and joy, red occupies the first place in signs, flags, publicity and other colors, and becomes the most powerful propaganda color, and it is more conspicuous under a white background. Therefore, it is better for cabo light boxes at the door of hotels to be scarlet letters on a white background.