It’s difficult to tell the age of this subject, as she looks mature, young, matronly and youthful all at the same time. The hair bow on the top of her head makes her look like a child in some ways and it’s not a flattering look. Her wide collar reminds me of the types of collars early teens wore in the 19th century, but at the same time her dress follows all the lines and style of a woman’s dress. She is an enigma, I’d guess about age 20. This is the top left of the second open page of the Dobb Long Book.
Speaking of the title of the book, when I was looking at it tonight I noticed it very specifically says Dobb “Long Book” suggesting that it isn’t two families, as Iggy speculated. I don’t know how I missed this when I introduced the book to you.
The photographer here was Hartley at 309 West Madison St, Chicago. A later example of the back of a cabinet card by Hartley can be found here showing “three immense floors alive with the best photographic talent possible to procure!” I believe this image in our collection to be from the early 1880s.