As Castle's paintings were usually photographed very soon after completion , the date of the pictures often provides a valuable guide to their dating. In the case of the sixty/odd paintings photographed by Georgina Lyn-Caryl, the order in which the works were taken is known (the negatives are numbered H.C.1, H.C.2, etc.), but there is no record of the dates and it is difficult to be sure where one batch ends and the next begins.
The Black-Boy Gallery have a series of albums with photographs of almost all the Castles that have passed through their hands. annotated with the titles and years and also, in a few cases, with a precise date or month.