Tuesday, August 29, 2017

The difficulty of photographing gold coins

Here are six professional pictures of the same coin.

These pictures appeared on the auction catalog or web sites of numismatic auctioneers Harlan J Berk, Classical Numismatic Group (twice), Heritage, Stack's Bowers, and the coin grading company Numismatic Guaranty Corporation.

These images were taken over the span of eighteen years. The version with the red background was scanned from a printed auction catalog. All of the other images are taken directly from auction sites or the slab company's slab verification image.

This coin did not change color in the last 18 years. Something about the lighting situation and the camera's color profile was different enough that each of these pictures is different.

What color is the coin really? In my memory the coin looks like the middle coin on the left-hand side. Yet when I held the coin over my computer monitor in a room lit by compact florescent lights it looked most like the upper right image.

Can the output of my computer be trusted? In the days of CRT monitors the color balance could be tuned and there were reference images for that purpose. LCD monitors are not as color-accurate as tuned CRT monitors. Perhaps I should repeat the experiment in the sunlight? Bottom-line: I am not certain which image is the most accurate.