В книге Luftwaffe colours есть английский перевод приказа, но он несколько странный. Впрямую не говорится, но подразумевается :-)
A night camouflage, RLM 22 Schwarz, was consequently introduced for this purpose.
On 16 July 1940, the Luftwaffe General Staff ordered the application of night camouflage paint: "Genst. 6. Abt (IIIB) Nr 7797/40. Secret.
To achieve a high degree of camouflage against search lights by applying a night camouflage paint, the air-craft's wing undersides, fuselage undersides and sides, must be overpainted with said paint, including all markings. The only exceptions are the Balkenkreuze on the uppersurface of the wing for national identification. It is essential that the overpainted Balkenkreuze can be restored by merely washing off the camouflage paint. As far as those aircraft intended for night operations are not yet camouflaged as described above, this should be done immediately. It is also brought to the attention of all concerned that prior to applying the camouflage paint the areas to be painted must be given a coat of insulating lacquier"