Finally, we examine the Raman spectra for samples where the pick test showed that failure occurred at the coating-paper interface. Samples falling into this category include the all- anionic and all-cationic coatings at 3 and 5 pph latex and all-anionic at 7 pph of latex. As with the samples where the failure occurred within the paper (both 10 pph and 7 pph all-cationic), the spectra for 3 and 5 pph latex samples show bands due to cellulose. However, the Raman spectra of these samples were different from the spectra of the uncoated paper in that there was a peak to SB latex. This band was not present in the spectra where the failure occurred within the paper.