Gemstones like precious opal are beautiful to look at and deceivingly complex. As you look at such gems from different angles ...

A color notation : an illustrated system defining all colors & their relations by measured scales of hue, value, and chroma made in solid paint for the accompanying color atlas / by A.H. Munsell ...

The elevated camera and automated image processing should appeal to those who take a lot of product shots. The rest of the machine is pretty good, but toner is ...