To paint a bumper, do you need to do anything else to it, like primer, or can you just spray paint it?

i have a front bumper to a 95 sonoma and its blue, my truck is white, can i just buy the paint and use it over the blue or is there more to it? also is there a certain kind of paint i need or can i use regular spray paint?To paint a bumper, do you need to do anything else to it, like primer, or can you just spray paint it?
You will need to slightly sand the surface and you will need to buy a paint that is a flex type additive so that it will not cracked when its hot or cold.





To get the correct paint just ask any good body and paint shop for the correct name of it...