Research Article
Characterization of Two Historical Postage Stamps Made from Cotton Fibers and Their Restoration Trials Based on the Experimental Studies
Table 3
Raman spectra from the reference and red stamp samples.
| Compound | Raman shift/wavenumbers (cm-1) | Reference sample | Stamp sample |
| Barium sulfate | 454, 464, 989 | 458, 460, 992 | Calcium carbonate | 283, 713, 1087 | 1017 | Kaolinite (silica) | 145 | 147 | Flax seed oil | 865, 1076, 1302 | 864, 1447 | Hematite | 225, 245, 294, 290–300, 412 | 295, 227, 412 |
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