The nineteenth-century Paris watch house of C. Detouche announced itself on paper like this: an engraved trade card dense with ornament, the shop's address on the rue Saint-Martin set like a jewel in its own case. Trade ephemera is the horology the histories skip — not the masterpiece but the handshake, the printed object a customer actually took home. The Carnavalet's scan preserves the plate work at a resolution the original cards never expected to enjoy.

Maker: C. Detouche (house), unknown engraver
Date: 19th century
Medium of the original: Engraving
Original held by: Musée Carnavalet, Paris
Credit: Musée Carnavalet, Paris · via Wikimedia Commons
Rights: Public domain, verified
Catalogue number: PA-00544

As chosen: 24 x 16 in, art print, classic frame
Picture	24 x 16 in
Outside size	25.6 x 17.6 in
Depth	0.9 in (22 mm)
Weight	[[REAL PROOF NEEDED: shipped weight per size and frame]]
Hanging	[[REAL PROOF NEEDED: hanging hardware Prodigi fits to this frame]]
Material	Enhanced matte art paper, 200 gsm; acrylic glazing
Made in	Charlotte, North Carolina, by Prodigi

Before a size goes on sale, the file is measured against it: pixels per inch at that size, how much of the picture a crop would lose, tone and sharpness. A size that fails is not offered, so there is nothing to choose wrong.

How the print check works

Sizes offered
Size	dpi	Grade	How it fits
12 x 8 in	354	Excellent	Trimmed 0.2%
18 x 12 in	236	Excellent	Trimmed 0.2%
24 x 16 in	177	Good	Trimmed 0.2%

Sizes withheld
Size	Why
10 x 8 in	Wrong shape: a 17% crop
14 x 11 in	Wrong shape: a 15% crop
16 x 12 in	Wrong shape: a 11% crop
20 x 16 in	Wrong shape: a 17% crop
24 x 18 in	Wrong shape: a 11% crop
30 x 20 in	141 dpi; a historical scan is never enlarged
30 x 24 in	Wrong shape: a 17% crop
36 x 24 in	118 dpi; a historical scan is never enlarged
40 x 30 in	Wrong shape: a 11% crop
48 x 36 in	Wrong shape: a 11% crop
60 x 40 in	70 dpi; a historical scan is never enlarged