The range of 20 seconds was only an illustrative example to make the point about wider intervals. The total range is whatever the printer thinks it needs to be. The point is the intervals should bear some relation to the total range, so that you get a decent portion of the image (preferably lights and darks) in each exposure strip. If the range is 60 seconds for example, I wouldn't suggest using 3 second intervals.
Originally Posted by smieglitz
Just keep it simple, people.