Inspired by the grey gene in horses.
A single copy will mostly cover the markings up so is referred to as fading.
A double copy completely covers the markings and is considered a true fade.
Fading Black - Fading Sooty - Fading Red Fawn
Fading Red - True Faded Shaded - True Faded Wildtype Fawn
Fading Wildtype - Fading Brindle - Fading Wildtype Fawn