Pewter of the Bronze Age in the Near East. The earliest piece of pewter found is from an Egyptian tomb from 1450 BC. The constituents of pewter were first controlled in the 12th century by town guilds in France. By the 15th century, the Worshipful Company of Pewterers controlled pewter constituents in England. This company originally had two grades of pewter, but in the 16th century a third grade was added. The first type, known as "fine metal", was used for tableware. It consisted of tin with as much copper as it could absorb, which is about 1%. The second type,
Photon etc. to identify. This is why a group of researchers from Aix Marseille Université developed a spectrally resolved characterization technique based on a supercontinuum source and a laser line tunable filter. The method is described in details in Liukaityte et al. paper from Optics Letter and allowed to study thin-film filters with optical densities from 0 to 12 in a wavelength range between 400 and 1000 nm. Photon etc. Photon etc. is a Canadian manufacturer of infrared cameras, hyperspectral imaging and spectroscopic scientific instruments for academic and industrial applications. Its main technology is based on volume Bragg gratings, which are used