“…Once the glass deterioration cycle starts, decomposition products are trapped and contaminate the microenvironment. 8,12,13 Barger et al categorize decomposition products found on the cover glasses as follows: amorphous gels, crystals found in these gels, products formed by the interaction of the gel with the surface or the brass mat or the underlying daguerreotype, and other products. Using primarily a combination of optical microscopy, SEM-EDS, and X-ray diffraction, sodium sulfate, barium sulfate, ammonium bromide, silver, silver chloride, silver phosphate, sodium formate, and cuprite were identified in these products.…”