Lakenvelder blue

Color and pattern male

Head and hackle: deep bright blue.

Shoulders: white.

Back: barely patterned, largely hidden by the hackle; lower back white with some shaft striping.

Saddle-hackle: white with broad shaft striping.

Tail: steering-feathers and sickles deep bright blue; coverts  deep bright blue, at the transition to the saddle hackle, faintly edged or tipped with white at the feather tips; outer row of coverts bright blue with a narrow white edge.

Wings: white wing-bar.

Primary-flights: inner-vane bright blue, outer-vane white.

Secondary-flights: inner-vane  bright blue with a narrow white edge that runs around the feather tip; outer-vane white so that when the wing is closed, it forms a white wing.

Front of neck, breast, body, thighs, belly and rear-end: white.

Down: light blue-grey to almost blue, it should not extend into the solid feather-field.

Serious faults 

Visible white in the neck-hackle. White in the tail steering-feathers. Blue on the breast, belly, thighs and wings. Rust on the wings. Lack of blue on the wing-flights.

Faults 

The above serious faults are present to a lesser extent. Some grey on the head. Insufficient pattern on the wing-flights. Far too dark or far too light blue. Uneven blue. Many black splashes in the blue feathers. 

Color and pattern female

Head: as bright blue as possible, but some white permitted.

Neck-hackle: as completely as possible bright blue on the surface due to the bright blue underside of the hackle feathers; some lighter pattern on the upper part of the hackle permitted.

Back and saddle-cushion: white.

Tail: bright blue steering-feathers and coverts, outer row coverts with a narrow white edge.

Primary-flights: inner-vane bright blue; oute-vane white.

Secondary-flights: inner-vane bright blue with a narrow white edge that runs around the feather tip; outer-vane white with a narrow bright blue edge against the shaft.

Front of neck, breast, body, thighs, belly and rear-end: white.

Down color: light blue-gray.

Serious faults

Visible white in the neck-hackle. White in the tail steering-feathers. Blue in the breast, belly, thighs, back and wings. Lack of blue in the wing-flights.

Faults

The above serious faults are present to a lesser extent. Insufficient pattern on the wing-flights. Far too dark or far too light blue. Uneven blue. Many black splashes in the blue feathers. 

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

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