All cotton, yarn dyed indigo. Most of the fading is due to wear over the last year. Lots of paint details, like it was worn during painting the hull of a boat. Looks similar to U.S.N. G.O.B. sweaters.
Front (the stitched detail on the neck) (some paint specks and naturally worn faded areas)
Close-up of paint detail and fade color
Detail of the color and the natural indigo brilliance