The first use, during the Battle of Britain between early to mid August 1940*, was a yellow segment on the top of the rudder of the Bf109, which, by 18th August, had extended to the complete rudder.
(*The exact dates are not recorded, but examples were seen between around 9th to 12th August, and beyond.)
This was soon followed by the addition of yellow wing tips and tail plane tips, with at least one Jagdgeschwader using white, which later changed to yellow.
By the time of the first massed raid on London, on September 7th, the wing tip paint was mainly removed, and the cowlings painted yellow, although some units retained the wing tip colours too.
From mid-August onwards, a combination of rudders, wing tips and cowling colouring could be seen, in the main, but some aircraft were noted without any of these.
On the BF110 at this period, when I.D. colours were used, this was mainly restricted to the nose area, and mainly white 'paint' was used.
This 'paint' was a distemper type, 'washable' colouring, which could be removed by 'washing' in petrol.