My problem is as follows. The original images were 3'x4' colored maps with very high detail including lots of little towns and rivers and symbols. The originals were transferred to 8"x10" positive transparencies. I don't know the technology but it was apparently quite difficult and performed at the National Archives. I have to scan hundreds of these transparencies during a five day visit to the Archives. Based on past experiences, in order to capture all the detail I have to scan at a minimum of 1800DPI and the scan time for each image can not exceed five minutes. The size of the image file is not an issue. I would appreciate any suggestions.