Titled in full as "young girl in high collared white blouse, with long hair suggesting informality", this Mason Collection image is indeed a little more casual and candid than the studio formality we tend to see in these collections. A more personal image from the Mason collection perhaps?
The community suggests that, if indeed this is perhaps (obviously unconfirmed) a family member, that it could be Sarah Mason
, who would have been in late teens or early 20s during the catalogue range ascribed to this image....
Contributor: Thomas H. Mason & Sons photographers
Collection: Mason Photographic Collection
NLI Ref: M57/10
You can also view this image, and many thousands of others, on the NLI’s catalogue at catalogue.nli.ie
Owner: National Library of Ireland on The Commons
Source: Flickr Commons