The work of Serg Shushyn a modern day ambrotypist. He works with the 19th Century wet collodion process - as did Lewis Carroll among others. An ambrotype is photographed onto a glass plate which has been coated with black varnish, so that the negative is the positive because the under exposed areas reveal the varnish. Development and fixing are done in the same way as the paper method which pre-dated glass plates and continued long after them. Unlike paper, a glass substrate has no grain, which allows a better capture of fine detail. How the images are digitalized I have no idea.