Paper marbling Turkish and Persian, which literally means Frankish. Historic forms of marbling used both organic and inorganic pigments mixed with water for colors, and sizes were traditionally made from gum tragacanth ("Astragalus" spp.), gum karaya, guar gum, fenugreek ("Trigonella foenum-graecum"), fleabane, linseed, and psyllium. Since the late 19th century, a boiled extract of the carrageenan-rich alga known as Irish moss ("Chondrus crispus"), has been employed for sizing. Today, many marblers use powdered carrageenan extracted from various seaweeds. Another plant-derived mucilage is made from sodium alginate. In recent years, a synthetic size made from hydroxypropyl methylcellulose, a common ingredient in instant wallpaper
Humic substance increases clay's plasticity. Supramolecular Humic Systems in the Environment (In English, original is Italian) Humic substance Humic substances are organic compounds that are important components of humus, the major organic fraction of soil, peat, and coal (and also a constituent of many upland streams, dystrophic lakes, and ocean water). For a long era in the 19th and 20th centuries, humic substances were often viewed through a lens of acid–base theory that described humic acids, as organic acids, and their conjugate bases, humates, as important components of organic matter. Through this viewpoint humic acids were defined as organic substances extracted from