Gums

Gums are complex polysaccharides, which are carbohydrates made of chains of monosaccharide units. They contain exudates obtained from some trees, shrubs, or algae. Gums are not only used as adhesives but also as paint binders and sizes. In general, gums are relatively weaker adhesives and can be distinguished from natural resins by their solubility. Resins are typically soluble in organic solvents, while gums are typically water-soluble. Two sizing materials mentioned that fall into this category in Persian historical treatises are gum arabic (samḡ-e arabi), gum tragacanth (katirā), and eremurus (seriš).