As computer monitors differ in their display of colors, color chart samples should be used as a guide only. The use of our Color Ring is the best way to pick out your color. This is especially true if you are picking out colors in the blonde family, as there are subtle differences in the blonde colors that are difficult to differentiate on a computer screen. For gray mixes, it is best if you send us a sample for us to match. Otherwise, you should specify how much white or gray hair we should mix with your base color.