See the bottom of the link which quickly defines the types. TYPE 1 is the most valuable/best/rare..etc..
http://www.psadna.com/photo_process.chtml
I also suggest you buy the book:
"A Portrait of Baseball Photography " by Fogel, Marshall and Khyber Oser and Henry Yee
The book will help you define types on your own and shed light on what is important in life.
