When it comes to analyzing samples with FTIR (Fourier Transform Infrared) spectroscopy, two common techniques are often employed: ATR (Attenuated Total Reflectance) and diffuse reflectance probes. While both methods serve the same fundamental purpose of capturing infrared spectra, they differ significantly in their penetration depth. ATR probes utilize the principle of total internal reflection to obtain spectra from samples’ surface of few microns, in practice, just the varnish. Instead, diffuse reflectance probes measure the infrared radiation reflected from the sample’s surface as deep as hundreds of microns, from the varnish to the canvas.
