>> okay, the picture is legit, but how about that signature? >> so, this is joe jackson's last contract. this is 1920. >> remember, nobody has seen another autographed shoeless joe picture. but steve can compare the writing to various legal documents that the illiterate jackson did sign. >> through the years i've been able see a handful of joe jackson signatures we've deemed authentic, and i'm able to look at certain tendencies joe jackson has. so, that autograph has to talk to me. if you want to go ahead and put it in... >> we put a copy of the signed photo into this contraption, called a video spectral comparator. >> you'll see things you can't see with the naked eye... >> let's see. >> ...you could see with this. and here we go. i'm gonna drop the magnification to 8. >> it's very "csi." >> and we start to look at the formations here of the letters. you can see where he's really -- he labored. >> he had a very hard time even writing an individual letter. >> he did. >> how do you...