Dark gray is a color that is a mixture of black and white. It is often described as a shade of gray with a higher proportion of black, giving it a darker appearance. The number '123' might refer to a specific shade or a code for the color in a particular system, like in color matching for printing or painting. In the RGB color model, dark gray can be represented by a combination of equal amounts of red, green, and blue (e.g., R: 123, G: 123, B: 123).