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Figure 5 | Heritage Science

Figure 5

From: Is there evidence for change to collagen within parchment samples after exposure to an X-ray dose during high contrast X-ray microtomography? a multi technique investigation

Figure 5

Principal components analysis of the NIR spectra of historical parchment samples. (a) A scatter plot of the eigenvalues of basis function 1 versus basis function 2 for the historical samples. (b) Log(1/R) spectra (bottom) of the 1769 (top) and 1832 (bottom) samples. The 1769 spectra shows a peak at 2310 nm which can be assigned to lipids, which is absent from the 1832 spectra.

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