Fig. 6

a Fluorescence spectra acquired from two white areas: one was an untreated control and the other treated using a mix of EOs at 1% concentration. The spectra were taken before and after the treatments. b The painted stucco remnant used to test the effect of essential oils by dividing it into different areas of the same size using a grid obtained with a transparent film and then covered with aluminium foil. c Reflectance spectra acquired from five areas before and after treatments (7T, black lines: white area treated with essential oils from Thymus vulgaris at 1%; 1C, blue lines and 1Cr, red lines: two red areas used as control; 2C, green lines: white are used as control; 4LT, orange lines: green area treated with mix of EOs at 10%)