The development of visible and near-IR LCTF-based spectroscopic imaging systems for macroscopic samples

Near infrared and visible spectroscopic imaging systems were developed which are able to acquire spectroscopic images of samples at a distance, completely without contact. These imaging systems were used to analyze two colour test samples and one 15(th) Century drawing from the Winnipeg Art Gallery. Spectra extracted from the quantitative test sample showed good linearity with ink levels across the visible wavelengths. By using wavelength images which match the wavelength sensitivities of the human eye, colour reconstructed RGB images can be created with good colour fidelity. Because of its ability to penetrate through some art pigments and inks, near infrared spectroscopic imaging was used to investigate lead-point underdrawings in ancient drawings in order to understand the artistic process better.