printing - what kind of paper is best

4 major characteristics of paper:

1. paper thickness
2. paper opacity
3. color brilliance
4. paper finish

ISO brightness is the standard that quantifies the brightness of paper as it would be perceived in a setting that is illuminated with a mixture of cool-white and unfiltered daylight.  ISO standard will always be brighter than TAPPI for the same paper.  ISO brightness can exceed 100% by a small number.

TAPPI brightness is the brightness of paper as it would be perceived in a setting that is illuminated in some cool-white fluorescence and some filtered daylight.  the UV component of TAPPI brightness is the lowest of any standard.  TAPPI brightness provides the lowest number of any of the three scales and rarely exceed 100%