I have some old burgundy tiles that I'm thinking of painting white. It doesn't really matter what it looks like because it's going on a wall at the back of a cupboard which will then have shelves all over it so won't see much of the paint. I just want to lighten it up a bit in there as there's no natural light. But I obviously don't want it to be peeling and flaking off... do I really need to use a special (ie. expensive!) tile primer and paint or can you use ordinary paint & gloss? Thanks!