To reinforce Sino's point, one of the strongest points that Les makes is to select the first strip from the soft grade filter test that shows detail in the highlights. If you choose too long an exposure your highlights will not be bright. The midtones and shadows get "filled in" with the hard exposure. And Rob, your point about the crosshatch method is correct. I usually use a half sheet for each test, making sure that the important highlights and shadows are included in the respective test strips.