RAF wwII Ladders shape and colors (question)

Hi guys,

1940-1941 era.
I would like to know the specific color, if there was any, (red, yellow, black, NMF etc.) of the metallic (aluminum) ladder, ”Λ” shape, RAF technicians used for maintenance purposes (engine etc.). Is there any possibility for someone here to know anything about that?

Thank you in advance,

Alex.