We are in possession of hundreds (thousands?) of what seem to be glass slides. The glass is 3-1/4 x 4, the image area is about 1-3/4 x 2-7/8. The images are very sharp and detailed, largely architectural but many other topics besides. What are these called? Has anyone had any success shooting regular slides from these? Or any info on a projector? Any help would be appreciated. Thank you. Ivy Fleck Strickler Phone 215-895-1637 Drexel University Fax 215-895-4917 Nesbitt College of Design Arts Philadelphia, PA 19104