I haven't looked at a Blue Book recently, but they used to have a section of color photos in the front of the book that illustrated various condition factors, including percentage of remaining case colors.
To me, a good description would be a total percentage remaining with further details such as "strong vibrant case colors in hidden areas, faded 40% remaining on action, and very little remaining on bottom of trigger plate and action." Seldom will a seller give such a description. As Ky Jon says, most of them see at least 90%, and price the gun accordingly. We are then free to laugh and remind them we weren't born last night. Paying a 90% condition price for a gun with 40% case colors is a certain way to be one of the guys who thinks we are destined to lose money on every gun purchase we make.
