HORSES CATEGORIES :
GREYS, REDS (CHESTNUTS and BAYS ), DARKS, PIEBALDS
GREYS: from white to dark grey with different shades of tones dappled or flea-bitten
CHESTNUTS : are recognizable for having the mane, tail and lower legs in the shaded color of the coat;
BAYS : are recognizable for having mane, tail and lower legs in black
DARKS, mostly recognized as blacks are the darkest tones of bays and chestnuts; the real blacks are rare.
PIEBALDS Rounded randomly with spots big (Piebald) or small (Spotted) in black or brown shades.
I have a table of colors which comprehend mostly of the categories, related to the Valleyo Acrylic color collection: (you can copy or drag the image to your desktop).
BASIC ELEMENTS OF THE HORSE COAT : (Graphics taken from Historex catalog)
COAT SHADES The horse coat has mainly a dark area (UPPER COAT) and a light area (LOWER COAT) this is the main distribution scheme.
DIRECTION OF THE HAIR GROWTH It is important to consider the direction of the hair growth for painting more accurate the coats. See the scheme
DAPPLING For grays the dappling areas are lighter and located like the scheme
For dark bays and chestnuts the dapples are like the following scheme
LEG MARKINGS Are in general irregular and not always present in all the four legs, in general ther extension is related to the head markings , see scheme:
HEAD MARKINGS Are often related to the legs markings, see scheme: