AI Appraisal Estimate

This is a hand-colored copperplate engraving of a map titled 'L'Ancien et le Nouveau Mexique,' prominently featuring the coastlines of California and the Gulf of Mexico. Created by the French royal cartographer Rigobert Bonne, likely dating from the late 18th century (circa 1780s). The map is printed on rectangular paper with a visible horizontal center fold, typical of maps originally bound in an atlas. It features hand-tinted borders in yellow and light green outlines along the coastline of Baja California and the mainland. The cartography includes French text, showing detailed topography, river systems, and settlements of the era. The item is professionally housed in a multi-layered framing system: a white outer mat, a thin pink inner accent mat, and a dark wood frame with a gold-tone inner lip. Regarding condition, the paper shows light toning and minor rippling, particularly along the lower edge and center fold. There are no major tears or visible foxing from this perspective, though a slight 'pinking' or oxidation of the pigments may have occurred over time. The craftsmanship reflects the high standard of 18th-century French scientific mapping, with fine line work and elegant typography.

I have conducted a visual examination of the map 'L'Ancien et le Nouveau Mexique' by Rigobert Bonne. This specific plate originated from Bonne’s 'Atlas de toutes les parties connues du globe terrestre' (circa 1780) and remains a significant example of late 18th-century French cartography. The plate exhibits early geographical depictions of the American Southwest and the Gulf of California. Based on the visible copperplate plate marks and the characteristic center fold, the item appears to be an authentic 18th-century engraving. The condition is good, showing minor age-appropriate toning and rippling along the lower margin. The hand-coloring is period-style, though the pinkish oxidation suggests some light-fastness issues typical of organic pigments from the era. The professional multi-layered framing adds significant decorative value, although it prevents an inspection of the verso for watermarks or mounting adhesives. In the current market, Bonne maps are widely collected and relatively available, which keeps prices stable but not exorbitant. High demand exists for maps showing California and the Spanish territories in North America. Comparables for this specific Bonne plate at auction typically range from $250 to $400 for the sheet alone; the current valuation includes a premium for the high-quality archival presentation. Note that this appraisal is based on photographic evidence. A definitive authentication requires an in-person inspection to verify the paper's laid lines and chain lines, search for the 'Grappe de Raisin' or similar 18th-century watermarks, and ensure the work is not a high-quality modern photolithographic reproduction. Provenance documentation regarding previous ownership would further solidify the valuation.