Fig. 4
From: Reflectance spectroscopy reveals mineralogy and preservation of ceramics from the Bidong Shipwreck
Component loading and mineral fit of powder samples for near-infrared range (700–2500 nm). (a) VPCA loading 1 (representing 33.09% of the spectral variance in the calibration data set) is similar in shape to the first derivative spectrum of hematite. (b) VPCA loading 2 (representing 27.51% of the spectral variance in the calibration data set) is similar in shape to the first derivative spectrum of gaylussite. (c) VPCA loading 3 (representing 21.01% of the spectral variance in the calibration data set) is similar in shape to the first derivative spectrum of sodium bicarbonate. (d) VPCA loading 4 (representing 8.55% of the spectral variance in the calibration data set) is similar in shape to the first derivative spectrum of illite.
