light modifiers: shoot-through umbrella vs bounce flash
With the contest where the light modifier had to be matched with the specific light pattern, there were clues in the images as to which modifier was used. The clues were in how the light was dispersed. Some were obvious, such as the hard side-ways shadow of direct flash with the camera held vertically. A dead give-away. But others were subtle .. but there.
For example, the image above shows the result, (used indoors in a studio situation) between the white shoot-through umbrella, and bounce flash with the Black Foamie Thing. (Click through the image to get to a larger version.)
A cursory glance at the two images will say they look the same. With more careful consideration, it will be apparent that the white shoot-through umbrella has a more contrasty image, and there is more pronounced light-fall-off across the background.