Given your stated exactness you'd probably see a difference, but the difference as I perceive it is so small as to be otherwise unnoticeable and I can use both Westminster (given to me) and white Rising Museum Board (resources) interchangeably, although I prefer to use the Rising as I believe it to be better board. This is particularly true for "matting" board in which there is very little reveal when floated in a window mat. Legion Paper, the distributor/supplier of Rising products, made a significant investment a few years ago in acquiring the faltering Rising Mill, and deserve the business.
Originally Posted by winger
Regarding LI, I too, have experienced the same problems obtaining the rare order during the past 2 years as others. While LI's customer service has never been that great, I believe they are not stocking many (or any) items and are ordering from suppliers on an "as needed" basis - when they have sufficient orders. Not a good way to do business, but perhaps necessary given the current economy. While not as convenient, my (rational) advice is to find other suppliers, and not to order from LI unless not time critical.