Brian, your comment about glass and gravity as opposed to spring tension is accurate in my experience. The same principle applies to spring tension as compared to the pressure exerted in a vacuum frame when one works with larger negatives and paper. Prior to buying a vacuum frame, I encountered not one person that told me that spring back frames equalled vacuum frames when one moved into ULF negatives. Had I found someone that shared a contrary experience with me then I would not have spent the money on the pump and frame. My experience with the vacuum frame has supported and reinforced what I was told.
Originally Posted by bmac
As I have related earlier I do use a 8X10 spring back frame when I do a limited number of prints of that size.