Grading on a curve? 0

[drotto]

I have often seen it talked about that there is a GA bump given be CGC, and on older books they tend to go a bit easier on the grading.  I was wondering is this just for GA or is there somewhat of a bump for older books in general.  I have sent in Modern books and been absolutely puzzled when they come back way lower than I expected.  On the other hand, I find that most books from the early BA back seem to come back higher than I expect.  I am starting to think their is not just a GA, but somewhat of a sliding scale that seem to start in early BA and gets more generous as you go further back.  

 

Am I off in my observations?  If you agree, what level of bump do you think CGC gives for each age as compaired to modern books?

[ADAMANTIUM]

I believe older (I don't know how old is needed) comics are made with different materials, so possibly there is a sliding scale or at least graded with different criteria..... Graded different as moderns now will be if there is another modernization of the current product. I think even golden age is different than SA and so on. Maybe someone with further knowledge will expound.