back in the day a. enamel was it. i love it. when its shot right its already glossy. but a old job that hass lost its gloss can usually be brought back to life if there was enough paint put on in the first place.there are 2 ways you can do it. one is to wet sand with 600 then 1000 or 1200 then buff it with a good compound or wet sand it with 1000 or 1200 shoot it with a high quality urethane clear, wet sand that with 2000 then 2500, buff that and presto shiny that looks deep.we do alot of that for customersthat have a old paint job(acrylic enamel) THAT STILL LOOKS GOOD JUST LOST ITS GLOSS.we have done it both ways and have not had a complaint yet