Cammo and aircraft painting.
Surely the best known of all of the "modern" camouflage schemes must be Nimrod XV246: The Brown Bomber or The Flying Mars Bar as it was variously known.
I did hear of a trial in RAFG which was a mix of aircraft with a variety of paint schemes. Canberra in green,VC10 in grey and Nimrod in hemp;there may have been more.They were parked on a hardstanding and were snapped by airborne cameras. The one which stood out was the hemp Nimrod. Did this then bring on the grey/blue colouring?