Outermost band – tertiary colour of yellow-orange (yellow + orange)
Second band – the tint of that tertiary colour (white added)
Third band – the tone of the colour (gray added)
Innermost band – shade on the print wheel (black added)

As you can see from the colour wheel shown above, the amount of white, gray and black added to a colour are minor—just enough to alter the original colour and to create what is known as a monochromatic colour scheme.
Monochromatic colour schemes

Colour schemes have been around for centuries, so there’s no need to reinvent the colour wheel. Although web colour differs from print colour, the concepts are the same. You just exchange hex numbers for colour names, and match then as closely as possible. One online tool I suggest using to help out with this is the Color Scheme Designer, as seen in Figure 3, which allows you to determine colour schemes quickly and easily, and even determine whether the colours you’ve chosen provide enough contrast for low-vision or colour-blind users.