A+ Mint condition, no imperfections in the image or blank margins, no restorations.
A Fine condition with no noticeable imperfections, good margins and good impression. May have small professional restorations at centre fold split or in margins.
B Good condition with minor imperfections such as light age-toning, small marginal tears (professionally repaired) or light offsetting.
C Fair condition with noticeable imperfections which may be: age-toning, wormholes, spotting, trimmed margins, repaired small tears entering image.
D Poor condition. Each imperfection is described.