[klemchen]

Hallo Horst,

thank you very much for your answer. I had expected that at unit level things were happening as you described them, but that still does not say what the official purposes of 04 and 27 were. Your answer seems to contain a hint that the original meaning of 04 was marking devices for fuel and that of 27 marking certain units (?).
If we can trust the authors of articles and books on Luftwaffe colors, in practicl usage 04 widely replaced 27, Perhaps this was so because a bright yellow like 27, when seen from a larger distance, tends to appear rather whitish, while this effect is weaker with a darker yellow like 04.

With best wishes,
klemchen