The cream dilution gene affects base colors by lightening them, a single dilution of the gene produces colors like palomino and buckskin. While a double dilution creates the light skinned cremello and smokey cream colors often mistaken for greys.
A double dose of the cream gene affects colors much more dramatically and can even make black animals almost pure white. Double cream dilutions are the most often mistaken for albinos (which don’t exist in horse genetics).
The champagne gene is a rather recent discovery in the world of horse color and it has a diluting effect on both chestnut and black base coats. This pigment alteration can exhibit in a showy display of colors which often have an almost metallic sheen.
Although it should be noted that not all horses with a metallic sheen are champagne.
Basic Champagne Gene
Sometimes born with blue eyes
Born dark and coat lightens with age
Sometimes born with pink skin which darkens with age
Freckling around mucus membranes common
Mistaken for appaloosa, sabinos and sometimes grays
Can have reverse dappling
Different Champagne Shades
The champagne gene affects black, chestnut & bay animals to varying degrees, here are some examples.
The dun dilution gene is generally quite obvious due to the specific (almost primitive) markings that indicate its presence. Some animals will display darker striping of the legs, withers and face and can be mistaken for asooty / smutty modifier.
The quick and easy way to determine a dun gene is to look for a dorsal stripe from mane to tail.