My son needs a passport photo and gor various reasons we want to take it ourselves. There are lots of white walls inside our house but we're struggling with shadows. I looked online to see if I could get a cheap (<£30) white backround for use in the garden but they are generally more than that (if they have a frame) and the cheapest get poor reviews. Any tips? (Last time we put a white sheet over the side of the trampoline but had a nightmare getting it crease free and flat).