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Table 2 Range of values measured for the absorption features in the reflectance spectrum and inflection points in the first derivative transformation of cochineal- and madder-based pigments in this study

From: Seeing red: towards an improved protocol for the identification of madder- and cochineal-based pigments by fiber optics reflectance spectroscopy (FORS)

FeaturesCochineal-based pigmentsMadder-based pigments
λshoulder~ 485–497 (∆ ~ 12 nm)~ 469–481 (∆ ~ 12 nm)
λabs,1520–538 nm (∆ = 18 nm)500–509 nm (∆ = 9 nm)
λabs,2555–574 nm (∆ = 19 nm)~ 538–548 nm (∆ ~ 10 nm)
1st inflection point496–503 nm (∆ = 7 nm)~ 486–490 nm (∆ ~ 4 nm)
2nd inflection point533–545 nm (∆ = 12 nm)520–524 nm (∆ = 4 nm)
  1. Some ranges are presented as approximations because the related features are present as shoulders in the spectra