Trinity College Chapel and Hospital with Calton Hill in the background, Edinburgh, mid 1840s, HA0758.

A significant amount of Hill & Adamson's negatives and prints had remained at Rock House through the changes of ownership, likely blended into several photographers' stock. Much was distributed elsewhere, by Hill and likely by others, and what remained at Rock House was a curious mix. Many of the remaining negatives were variants of better known ones. Some were perhaps considered technical failures at the time, although their historical value is hardly diminished by this. And the negatives for some of their most famous images stayed at Rock House. In 1941, the pioneering photohistorian and collector, Robert O. Dougan, approached Francis Caird Inglis' widow and arranged to purchase all of the material relating to Hill & Adamson. There was no detailed record of the contents of the collection made at the time. Although it is likely that some items were deaccessioned from this group, it must have remained largely intact. When Dougan, then City Librarian of Perth, accepted a post in Ireland, he realized that he wanted the collection to be kept together and he wanted it to be kept in Scotland. He arranged to sell the collection in its entirety to the Glasgow University Library in 1953. The first exhibition from the collection was mounted in the Hunterian Art Gallery the following year

There are some mysteries about the present collection and the Library records from the 1950s are sparse. However, the earliest mentions of the collection count 490 negatives and "nearly 500" prints. This is exactly the number of negatives presently in the collection and about right for the print count. It is known that some of the prints were in albums when they came to the University and that early on they were removed from the pages by a paper conservator. As would have been common practice at the time, no records were kept of the contents and collation of the albums and the carcasses were not preserved. However, many of the prints have traces of glue on the verso, indicating that they were removed from a mount. Many prints are stamped "A" or "B". The glue patterns are consistent within these groups and it can be speculated that there were two albums in addition to the loose prints in the collection.

Some unknown portion of the collection also came from the Annan family. James Craig Annan was a master of carbon printing who took a great interest in Hill & Adamson's work around 1900. His great-nephew, John Craig Annan (now deceased) recalled that in 1946 his father "gave all the papers, etc., of J. Craig Annan, to the University together with his D.O. Hill negatives." No inventory of this donation has been traced in either the Annan archives or in the Library's records. It is almost certain that the hundreds of carbon prints and glass copy negatives in the collection came from this Annan donation. It is also possible that some of the original calotype negatives or salted-paper prints in the collection came not from Dougan but from Annan.