I painted some MDF kitchen shelves using emulsion, but didn’t realise until I finished painting that MDF needs to be primed. Is there a way to prime the MDF after painting (ideally with a matt finish)?
You will be ok, use a 150 grit sandpaper to remove the knibs all over and give the shelves 2 or 3 more coats, normal matt emulsion may not be the best choice for shelving perhaps use Dulux Diamond Matt or even Dulux Diamond Eggshell as it is a very tough paint.