Color Under German Wings
by Charles Metz
Color under German Aircraft is a complicated subject about which many books and articles have been written (e.g., see the “Luftwaffe Camouflage & Markings/Luftwaffe Colors” series published by Kookaburra and Arco in the 1970s, or “The Official Monogram Painting Guide to German Aircraft 1935-1945” by Merrick & Hitchcock, published by Monogram in 1980).
To simplify greatly: a light greyish-blue called “RLM 65” was used on Luftwaffe fighters with two-tone green or grey & green upper surfaces until around 1941 and on Luftwaffe bombers etc. with two-tone green upper surfaces until around 1944, whereas a light bluish-grey called “RLM 76” was employed after those dates. I recommend that you try to determine from kit directions or references which of the two colors was used on the particular aircraft you’re building, and that you then look for bottles of your favorite brand labeled “RLM 65” or “RLM 76.”
However, a lifetime of research on this subject might also be helpful if you want to avoid the possibility of being challenged on whichever color or interpretation thereof you choose.