As i understand it .....at the very onset German Army (and Navy) vehicles were as mentioned painted dark grey (panzergrau) and vehicles of the Luftwaffe a blue grey colour.
When the forces began to expand whitemarkings were used on wheeled (halftrack) vehicles (on the mudguards ) to aid the visability of the vehicles at night to others.
All the vehicles sent to N.Africa were also initialy painted Panzergrau, though special clothing, personal equiptment etc was designed and issed to all troops the continental patterns and colours were still worn by those who chose to.
A yellow paint (Ordanance Tan RAL 800) superceded the panzergrau some time in 1943, meaning that all vehicles fresh from the factory were sprayed/painted this colour, however this colour was also supplied to the Afrikakorps befor this time and vehicles weapons helmets were sprayed at local/unit level.
To aid concealment / camoflauge ,ocres of red and green were also issued to the desert then to the Mediteranean troops. These three colours formed the basis of German camoflauge schemes untill the end of the war (excluding winter warfare) from the basic yellow through to the complex butterfly camos seen in northern Fance etc.
Just a brief overview :-)
Ashley