For example, If you want a semi-transparent version of blue, just find the hex for blue (#0000FF) and prepend the 2 digit hex value for the transparency byte (aka alpha channel) to create something like #800000FF. Note: “80″ is 128 in hex, 128 is half of 256 (the maximum), meaning this will create a 50% transparent blue. Note: I recommend using the Opacity property over a transparent color when applicable but sometimes you need a transparent color rather than a transparent control.