Just found out from Fuji that the Acros 100 4x5 quickloads are not on a polyester base and therefore do not qualify for the most stringent Library of Congress archival standards (500 years). Maybe this is old news to HABS-HAER photographers, but I couldn't find it anywhere. I was hoping to use the ACROS quickloads for a couple of projects. looks like i'll be shooting the TMAX readyloads (on Estar thick base). Here is the response from FUJI: Dear Mr. Schafer, Thank you for contacting FUJIFILM, USA's Helpdesk Center. Please allow us to assist you. Acros 4x5 black & white quickload film is a cellulose triacelate base.