I purchased about 500 sheets of 8X10 a year ago. I am sure that this is really old since it includes grades one and four in addition to grades two and three. I have found that it is a better paper then current Azo. Reports are that early Azo had cadium incorportated in the emulsion and it absolutely glows. The cadium was latter eliminated for environmental considerations. On the old Azo I have noticed that in 6-128 selenium that it will split tone with the print values IV and below going to a faint red while the balance of the print values will hold a slight greenish tone. That can be both a boon and a detriment depending on what effect you want to achieve. This paper will last for a loooong time. I have heard people printing on Azo that has been over 60 years old. A lot depends on how it has been stored...if the original wrap is gone then it will probably not be good.