Multiple microspectroscopic imaging techniques have been employed to reveal the chemical and structural nature of flax (Linum usitatissimum L.) stem tissue, with the goal of finding the best technique by which to monitor retting processes for the production of linen fibers. Three of these techniques, which we have investigated for this purpose, are: mid-infrared (MIR), Raman and nuclear magnetic resonance (NMR) imaging. Initially, all three techniques were evaluated on the basis of their ability to reveal the nature of unretted flax stems. MIR imaging was found to be the most useful for this purpose. Thus, it was selected as the method of choice to follow retting processes to obtain flax fibers.

A Fourier transform (FT)-IR spectrometer equipped with microscope was used to acquire the MTR images. A FT-Raman spectrometer that was equipped with a Raman microprobe and utilizing a 1064 nm laser source was used to collect the Raman images.