FWIW, the HSCA determined that the blow up of 133a came from the original negative. Since this negative was never handed over to the WC, this means the DPD "lost" this negative.
Or does it? The HSCA testimony off Robert Studebaker, which is now available on the Mary Ferrell website (thanks to some dweeb named...Pat Speer) indicates that Studebaker made numerous copies of the BY photos using a copy camera, and that the blow-up of 133a was in fact a photo of a photo. This, moreover, was also the position of DPD crime lab employee Rusty Livingstone in First Day Evidence.
If this is true, for that matter--that the blow up to 133A was in fact a photo of a photo--it means the photoanalysts for the HSCA couldn't tell a photo of a photo from a first generation print, which is to say they could not tell s from Shinola, and that their authentication of the BY photos is meaningless.