Evidence based on ancient manuscripts of paper and tad-patra, written with a long lasting and hard wearing indigenously produced black ink, indicates this ink to have been in use for at least a thousand years. The writing in the Dasa Bhumiswara Mahayana Sutras (6th century) and the Astasahasrika Pragyaparamita (10th century) stands testimony to this.
This black writing ink was used in most government offices in Nepal – for official documents and accounts – till the coming of democracy in the state when imported papers and inks came to be widely used since this indigenous ink could not be used for filling fountain pens. However, traditionalists, astrologers, and artists, among others, continue to use the traditional black ink that is still made in Lalitpur. This ink was used for writing and illustrations on harital paper and on the ivory lokta bark paper.
PROCESS & TECHNIQUE
Modern writing inks contain gallic acid, tannic acid, and ferrous sulphate. Some aniline dyes are added for temporary colouring. The traditional Nepalese ink is an emulsion of colours. So shellac and other ingredients form a heterogeneous mixture; possibly, the resin and the soot do not have any chemical reaction.
One of the chief ingredients of the black ink is lamp black or soot. If only a small quantity of ink is required it is prepared by lighting an oil based earthen lamp (maka dalu). A cotton wick soaked in mustard oil is placed in the lamp base and its wick end is lit. Simultaneously a small clay-bowl is inverted over the lamp base. As the lamp burns the soot is deposited on the inside of the upturned clay bowl.
If a larger quantity of ink is required a small oven is lit using a resinous pine wood (diyalo) – found in the Himalayan regions – which burns with a luminous flame. A clay bowl (bhigut) is inverted over the oven – as the firing progresses, the bhigut gets covered with soot on the inside. When this inverted bowl gets heated it is replaced. Often, a copper vessel (phosi) is used instead of the clay bowl.
To prepare the black ink a proportion of water is added to a mixture of soot and hirakasi (iron sulphate). The mixture is then sieved through a fine cloth. The product is the black writing ink. Borax, imported from Tibet was earlier used for giving gloss to the letters written in ink.
The soot collected by burning the diyalo wood consists of carbon in its purest form. The soot does not dissolve in water, but when mixed vigorously, it forms a very fine emulsion with the ferrous sulphate solution and results in a deep black colour of great permanence.
Laha – a variety of black ink – is prepared by combining powdered raw lac or shellac to water and boiling the mixture. The lac melts in the boiling water and the solution becomes brownish. The boiling is continued till the volume is reduced to a quarter. Next, a small quantity of this mixture is put into a black stone mortar (gaji khal) and a small quantity of black soot is added. The mixture is ground and more and more soot is added during the grinding until the required consistency is reached. Then borax or glue is added and mixed in – this provides lustre and gloss to the ink. The ink is then stored in clay containers till required. The writing in this ink is done with the traditional bamboo pen called sir kalam.