White blacktail

Color and pattern male

Plumage: completely white except for the black pattern on the primary- and secondary-flights and the black tail feathers; a few small black feather tips are permitted at the lower neck-hackle, which must not degenerate into a greater black tip. 

Primary-flights: black with a white edge, which should be sharp and not too broad.

Secondary-flights: black with a wide white edge on the inner vane, outer vane is white, so that when the wing is closed it is almost entirely white.

Tail: steering-feathers black, the sickles are black with a white edge, and the shafts are light; In contrast, most males have such a wide white edge on the shorter sickles that they are predominantly white.

Down: white or gray, but gray down must not penetrate the top color.

Serious faults

White patches on the tail steering-feathers. Absence of black on the wing-flights. Black feather tips at the lower neck-hackle or a distinct striped pattern. Some yellow tinge in neck, saddle and shoulders.

Faults

Too much white on the large sickles. Insufficient pattern on the wing-flights.

Color and pattern male

Plumage: completely white except for the black tail feathers; a few small black feather tips are permitted at the lower neck-hackle , which must not degenerate into a greater black tip.

Primary- and secondary-flights: similar to those of the male

Tail: steering-feathers black, except the top feathers on each side, which must have a narrow, sharply defined white edge; a narrow white edge on the other steering-feathers is permitted; coverts black with a narrow white edge; completely white coverts are permitted.

Down: white or gray, however, gray down must not penetrate the upper color.

Serious faults

White patches on the tail steering-feathers. Absence of black on the wing-flights. Yellow tinge. Black feather tips at the lower neck-hackle or a distinct striped pattern.

Faults

Too broad white edging on the tail steering-feathers. Insufficient pattern on the wing-flights.

Genetic code: https://kippenjungle.nl/Overzicht.htm

Website with all available information regarding chicken genetics including the chicken color calculator.