Hello All....  I have a wedding coming up that requires a diagonal separation of 4 tiers from white to navy blue.  I would like to airbrush the color to get the best finish but I am not sure how to avoid overspray onto the white area.  All the tiers with be fondant covered.  All suggestions are very welcome!  Thanks for you help :)

Somebody may have a better idea but just cover the white parts. I have used blue painter's tape before (brand new). 

Thanks for the reply...  I was thinking of using painters tape and light weight plastic to create a "tent".