Ancient ink was often carbon-based, but was also made with metals like copper, which, sometimes, was concocted with little or no sulfur. During the Roman Empire and towards the medieval times, we notice a move towards the famous iron gall inks (made with iron sulfate) which became popular and remained so until modern times. A good example for the transition can be seen in the Coptic fragments of the famous, only recently re-discovered Gospel of Judas which links the ancient world to the modern, as the scribe used iron gall ink that also included black carbon soot bound with a gum binder.
This move is interesting also from a health perspective. Although iron sulfate in larger quantities are dangerous for the human body, smaller quantities are even used as general iron supplement in humans without any reports of adverse long term health effects. The added Oak gall apples' fluid (produced from cooking Oak gall apples for half an hour) were also a natural product. Oak gall apples grow on Oak trees, induced by wasps and their eggs.
For a long time, people have seen the beneficial benefits for women’s health and general health as well from Oak extracts. These have natural antiseptic properties that are effective in eliminating bacteria, yeast and fungal infection, the main cause of itching and unpleasant odor in the intimate area. Hence the gall apples did not only physically protect the wasp's egg, it did so also biologically.
As binding material, the Romans used Gum arabic, a natural gum made of hardened sap that is taken from two species of the acacia tree and links the Roman economy to central Africa and the Senegal or Somalia, although the species have also been historically cultivated in Arabia.
Now, Gum arabic is famous still today as source of the sugars arabinose and ribose and better known
in the food industry as an edible stabilizer (E number E414). As in antiquity, where it was (and in some countries still is) used to make a chilled, sweetened, and flavored gelato-like dessert. It is the basis for many soft drink syrups, "hard" gummy candies such as gumdrops, marshmallows, chocolate candies, and edible glitter, or for popular modern cake-decorating staple.