GUM ARABIC (SAMḠ-E ARABI)
Gum Arabic is the oldest natural plant polysaccharide, a dried exudate obtained from the branches and stems of acacia trees. It has been used by humans for more than 5000 years. Gum Arabic is obtained from acacia trees belonging to the family Leguminosae, which comprises around 900 species worldwide. The largest production of Gum Arabic comes from regions in Africa, such as Sudan, Nigeria, Mauritania, and Senegal. It is then supplied from Arabian ports, which is why it is called Arabic gum.
Recipes:
Different types of gums and their medical benefits are mentioned by Abu Raihān Biruni in Al-Saydaneh fi al-Tebb (440 A.H./1048 A.D) and Jamali-ye Yazdi in Farrokhnameh (580 A.H./1184 A.D), including gum arabic. Biruni has highlighted that the best gum is gum arabic.
بهترین صمغ عربی، شفاف و پاک از چوب است. این صمغِ اُمّ غیلان است
The best gum is Arabic, which is pure and transparent. It is obtained from the acacia tree.
Gum Arabic is mentioned in several historical recipes and is recommended for use as an adhesive and binding medium. Teflisi (12th century), Neishāburi (12th century), Serāj Shirāzi (15th century), among others, have included Gum Arabic in their recipes. Additionally, it is specifically suggested for paper sizing in treatises such as Resaleh-ye Joharrieh (15th century), Resāle dar Bayān-e Kāḡaḏ Morakkab va Ḥall-e Alvān (15th century). In Golzār-e Ṣafā (16th century), Ḵaṭṭ va Morakkab (16th century), and Resāle dar Bayān-e Tariqe-ye Sāḵtan-e Morakkab va Kāḡaḏ-e Alvān (19th century), Gum Arabic is described as a very good sizing material suitable for writing. However, the recipes are often brief, providing minimal details on the usage of Gum Arabic. For instance, in his treatise Ḵaṭṭ va Morakkab (978 A.H./1571 A.D.), Hosseini Aqili Rostamdari briefly mentions Gum Arabic.
نوعی دیگر آن که صمغ را آب کنند وکاغذ را بدان آهار کنند .....
... and furthermore, dissolve gum arabic in water and size the paper with it.
In one of his couplets in Golzār-e Ṣafā, Seyrafi (950 A.H./1543 A.D.) mentions gum arabic as the last material for sizing:
صمغ است دگر آخر کار این همه هست به جای آهار
Gum Arabic, last in line so fair,
In sizing's realm, a sovereign's share
Experiment:
Add 100 ml hot water to 10 grams of Gum Arabic powder in a ratio of 10:1 and stir it. Let it sit overnight until you get a smooth gum. Add water if it is too thick. Transfer the gum to a tray or glass container. Dip the paper in for an hour. Alternatively, apply the gum with a brush smoothly, depending on the consistency. Let it dry and burnish the paper.