English pewter 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, known as "trifling metal" or "trifle", was used for holloware. It is made up of fine metal with approximately 4% lead. The last type of pewter, known as "lay" or "ley" metal, was used for items that were not in contact with food or drink. It consisted of tin with 15% lead. These three alloys were used, with little variation, until the 20th
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