Light reflection in photography
In the professional field of photography, reflectors are used to brighten dark areas of either what is being shot or the surrounding of the subject. To design a self-made reflector, cut out a card board or mat board to your desired size and shape.
Use rubber cement to cover up the board. Using an aluminum foil, cover the board with the shiny side facing outwards. One reflector can be helpful but it is more convenient to design trio reflectors that are joined together for easy portability.