They might have been made by contact-printing from the original glass 10x8 negatives, and made as whopping big lantern slades (I would love to see the lantern...)(posted 9613 days ago)For reproduction, your bes bet might be to re-photograph them. The museum may have the facilities to do this. So you then have negatives (35mm, 5x4, or whatever), which can then be printed in the conventional way. They can also be digitised, and restored digitally, or displayed on you web site.