The basic ingredient of the black ink used is carbon, usually soot collected from the bottom of cooking pots or from kerosene lamps. To act as a binder roasted grains of maize, barley, or finger millet are infused in a small amount of water before the liquid is decanted off and added to the soot.
The juice of the fruit from certain Solanum species is often incorporated into the mixture at this point as it is a natural insecticide and keeps flies away.
These ingredients are mixed on a grindstone or stirred in a pot each day for a period of perhaps several months. Eventually a skin forms on the top of the mixture and this layer is skimmed off and dried into blocks.
This dried ink is stable for many years and small amounts can be mixed with water in an inkhorn to give liquid black ink whenever required.
Red ink is normally only used to write the names of God, Christ, Mary, and Saints and Martyrs. It was traditionally prepared from natural ingredients such as red flowers and red soils but very few scribes do this today. Usually commercial red ink is bought and then mixed with a binder such as acacia gum to thicken it.