Homemade Reflectors

any light coloured (or white) surface that reflects light would do really. normally i just use a white cardboard. it reflects a smooth and not too hard light. but i'm just a hobbyist. not a professional :P

Foil, mirrors and similar material fixed to card is equivalent to a spotlight - very sharp shadows, bright highlights and an excessive dynamic range for most purposes. For portraits and most group shots. a sheet is fine - just roll it up and carry it with you - it is also large enough to do the opposite task of blocking excessive light. Plain white card is fine and so is poly sheeting - just be careful that the reflected light does not convey a colour cast onto your subject. Even if it is really white (or whatever colour you choose), combined with the colour of the ambient light, it can fool your camera's white balance system.

I use mirrors, white cards, big reflectors with silver and golden foil surfaces, which I made myself. Everithing that reflects light could be used. But in the end of the day it is better to buy some 5 in one set of reflectors. They aren't so expensive.