Fig. 9From: Exploring elucidation of red dye mixtures on woolen historical textiles via non-destructive spectroscopic analysis and multivariate cluster analysisa Predicted vs. Measured plot for the linear model relating PC 1 of the FORS inflection point PCA (579–629 nm) to the preprocessed variable selected XRF spectra. b Residuals vs. swatch plot to assess if a linear model is appropriate for this dataBack to article page