Similar to RGBA values, hexademical (hex) color codes control the amount of red, green, and blue light. They also control transparency with a two-digit hex number, each starting with a hash sign '#', for instance, '#81d8d0ec'. Therefore, pure red, green, blue, black, and white's hex codes are '#ff0000', '#00ff00', '#0000ff', '#000000', and '#ffffff', respectively.