M. Newcome Schleier, Bartolomeo e Domenico Guidobono, Turin 2002, p. 122, cat. no. P58, reproduced pl. XLIV.
Mary Newcome Schleier (see Literature) publishes this painting as a work by the Guidobono brothers, perhaps by Domenico rather than his elder sibling Bartolomeo (1654-1709). The brothers, active in Savonna, Turin and Genoa, worked in both fresco and oil. They often collaborated, making their work sometimes difficult to distinguish.
The following condition report has been provided by Simon Parkes of Simon Parkes Art Conservation, Inc. 502 East 74th St. New York, NY 212-734-3920, email@example.com, an independent restorer who is not an employee of Sotheby's.
This work seems to be clean and retouched. The lining is probably slightly older than the restoration to the surface. The surface is even and well varnished. The retouching is quite accurate. Retouches are very thorough and numerous in the faces, the piece of paper and in some of the hands. The lighter part of the smock and dress worn by the older sister also shows retouches. The darker clothing seems to be healthier. The background has presumably received retouches as well. Some of the retouching is slightly elaborate, particularly in the mouth of the older sister, which can easily be re-examined. "This lot is offered for sale subject to Sotheby's Conditions of Business, which are available on request and printed in Sotheby's sale catalogues. The independent reports contained in this document are provided for prospective bidders' information only and without warranty by Sotheby's or the Seller."