this on pinterest, and thought I'd give it a test drive this weekend before trying it with the kids (the pin hole in the straw is a pretty nifty tip). I couldn't find any tempera paint, so I don't know how well that paint works, but ordinary washable paint didn't seem to have much affect on the bubble's colours. It is possible I needed to use more paint than I had available. However, food colouring did work. For the best effect I blew a whole bunch of bubbles and then dropped in the food colouring, it had the added bonus of looking super cool too!