From Al Ferrari ..... "Can you explain why in comparing Impact to Roll Score, one would do a better job than the other?"
You have to realize that, when you are looking at digital print (especially one with a lot of color coverage), what you are actually looking at is, a kind of melted toner particles (picture a thin film of melted plastic) that has been "cooked" on to your paper. If you bend it, that "plastic" will crack. While we have had a limited amount of success with "creaser" rollers, the problem with a "rolled score" is that the pressure starts on one side of the paper, then rolls to the other side. This rolling causes "un-even" pressure to be apllied across your page at varying locations along your score line. Remeber the "plastic film" image? If you apply un-even pressure to any kind of plastic --- it will crack. An "impact crease" hits your score line all at one time, in the same instant. Now, that score or "crease" in your "plastic film" has not only creased your paper, but, has rendered that line in your "plastic film" much more flexible, while, at the same time "hammering in" the "plastic film" along that line to prevent the cracking.