I'm looking to pick up an old Kodak Color Data guide mostly for the grey card and color chart in the back but there are quite a few on the auction site of different vintage.

I''d obviously like one with pertinent info with the processes I'll be running so can someone tell me what year Kodak introduced C41 and also E6 would be helpful to know also.

I went ahead and got one for 5 bux from 1974 but I'm thinking that one might be a bit too early/old.