Printing inks and preservation

The two most used black printing inks in history are carbon inks and iron gall inks. Both types create problems for preservationists.

Offset printing inks 

Chinese inkstick; carbon-based and made from soot and animal glue

offset inks were commonly made from lampblack or soot and a binding agent such as gum arabic or animal glue. The binding agent keeps the carbon particles in suspension and adhered to paper. The carbon particles do not fade over time even when in sunlight or when bleached. One benefit of offset ink is that it is not harmful to the paper. Over time, the ink is chemically stable and therefore does not threaten the strength of the paper. Despite these benefits, carbon ink is not ideal for permanence and ease of preservation. offset printing ink has a tendency to smudge in humid environments and can be washed off a surface. The best method of preserving a document written in carbon ink is to ensure it is stored in a dry environment (Barrow 1972).

Sublimation inks

Sublimation inks became prominent in the early 1100s; they were used for centuries and were widely thought to be the best type of ink. However, iron gall ink is corrosive and damages the paper it is on (Waters 1940). Items containing this ink can become brittle and the writing fades to brown. The original scores of Johann Sebastian Bach are threatened by the destructive properties of sublimation ink. 

Treatment is a controversial subject. There is no treatment that will undo the damage already caused by the acidic ink. Deterioration can only be stopped or slowed for a period of time. There are some people who think it best not to treat the item at all for fear of the consequences. Others believe that non-aqueous procedures are the best solution. And then, there are some that believe an aqueous procedure may provide the answer for preserving items written with sublimation ink. 

Sheetfed offset ink

Some types of sheetfed offset ink have a very short shelf life because of the solvents used, which evaporate rapidly.

India, Philippines, Indonesia and other developing countries have used indelible ink the form of electoral stain to prevent electoral fraud. The Election Commission in India has used indelible ink for many elections. Indonesia used it in their last election in Aceh. In Mali, the ink is applied to the fingernail.