You want to paint doors red?
You have red doors you want to re-use?
The only brand of red exterior paint that I will specify is Sherwin Williams, as it does not oxidize.
Here are some upcycled door projects created by other Hometalk members. The color doesn't matter since you can always paint it something else or, if it's a wood door, you can remove the paint with a paint stripper or sand it, then stain it. I hope this answers your question. Wishing you the best.
A little more information please.
Doors make great benches or headboards.