This is a photographic print from a cliché verre. Talbot has used the cliché verre as he would one of his paper negatives.
In the days of photography, cliché verre was a process that was usually associated with artists rather than photographers. A sheet of glass would be coated with a substance which the artist could scratch an image into. It is, essentially, a simple form of etching directly onto glass. Talbot realised early on that he could use a finished cliché verre to produce a photographic copy by placing the glass directly onto a sheet of sensitised paper before exposing it to light, just as he did with botanical specimens, leaves and fragments of lace.