Place enough water to cover your eggs in 2 separate bowls. Add red food coloring to one & blue food coloring to the other, whisking, until you get the color you desire. Place half your peeled hardboiled eggs in one bowl & the other half in the other. Put them in the fridge & let sit for 2 hours for the colors to set in.
Remove the eggs from the colored water with tons onto a layer of paper towels. Dry completely. Cut in half, remove the yolks, & make your deviled egg filling the way you want. Here's my favorite recipe for deviled eggs.
Keep the deviled eggs in the fridge until ready to serve.