Set up a simple still life shot. Shoot from the same level as the object, with the camera on a tripod. Fix the light at about 2-3 feet to one side of the object and at its level, so that it is aimed at right angles to the camera's view.
Take the first photograph without a diffuser in front of the lamp, and the second with the diffuser. Follow these with five exposures. The light and camera remain unchanged.
Take some white card and place it three feet/one metre away from the object, on the opposite side from the light and facing it. Take a photograph and then move the card twice as close to the object for the next photograph.
Tear off a piece of aluminium foil sufficient to cover the area of the white card and place it against the card, with dull side facing the object for the next exposure. For the next shot, turn the foil around so that the shiny side is facing out.
For the last shot, crumple the foil and then smooth it out again. Place it once more against the card, with the shiny side facing out.
Compare the results and place them in order of contrast, from the one with the biggest difference between the lit and shaded parts, to the least.
White card at one metre
White card at half a metre
Foil (matt surface)
Foil (shiny surface)
What have I learned?
The image with the most amount of contrast was taken with undiffused light. Using white card provided fill light and this increased as the card was moved closer to the subject.
A silver surface is more reflective than a white one, so the foil provided more fill light. By crumpling the foil and then smoothing it out, increases the reflective surface area as it is not completely flat, and consequently this produced the greatest amount of fill light.