Since mid-1941 USAAF adopted a standard camouflage of Olive Drab No. 41 (with blotches of Medium Green No. 42) over Neutral Grey No. 43. The scheme was used till late 1943, when use of camouflage by USAAF was mostly abandoned.
HTK-C004 – US Olive Drab 41 (Early) – Standard base colour of upper surfaces of majority of USAAF aircraft from June 1941 until late 1943
HTK-C019 – Medium Green 42 – Used from mid-1942 for blotches along all edges on upper side of the wing and tail, also on the fuselage sides
HTK-C033 – Neutral Grey 43 – Standard colour of lower surfaces of USAAF aircraft in “Olive Drab” schemes from June 1941 till late 1943