From paper to Sony - part 4 (more on lighting)
The angle between the lamp and the book page can be anything (usually 45 degrees) as long as the reflected at 90 degrees light does not go into the camera lens.
For uniformity of lighting the best thing is natural light outside, an apartment corner with two windows at 90 degrees or a bright lamp as high as possible (a bright ceiling lamp will do) over the cradle plus a diffusor. The v-cradle assures the proper angle.
Typical setting of two or four repro lamps at 45 degrees to the book page may work with very expensive lamps that I cannot find even in best photo shops (however there are some ads on the net). But in my experience, even if you see no bright spots on the page, the reproduction will show them. Human eyes provide for automatic correction, while the camera is not forgiving at all (photographers who deal with RAW pictures know it too well).