I love the several books on museum quality original horns with scrimshawed designs and lettering. I can look at them for hours. However I find that some horns I made in the 1970's seem to show more wear on the "body" side and more fading of the inking than many originals 250 years old. They must have had some super ink and done some deep work back then. Wow, some of those designs really "pop".
Rich,
Some horns wear in use more than others. The hardness/densifty of horn varies widely. I have had some cattle horns that were rather soft while others were rather hard.
As to the ink.
When you look back at that period of time there were two major forms of ink in use.
"Oil blacks" go way back in time. Until the 19th century these oil blacks were made on a fairly small scale. They took an animal or vegetable oil and burned it on wicks in a chamber with a limited air supply. Specifically to produce incomplete combustion with a "sooty" flame. Suspended over these wicks were glazed porcelain plates or disks on which the soot would collect. These were then periodically removed from the chamber and the oily soot removed. These oil black inks were the most expensive to produce.
As a horn ink it would require some sort of binder to bond it to the horn. Old formulas sometimes used shellac as a binder with alcohol in the water carrier to dissolve the shellac. Since the horn structure is slightly porous the shellac will act as a binder when dry.
Then there was the common writing ink using a mixture of ferrous sulfate ( copperas) and either tannic acid powder or gallic acid powder. Gallic acid powder was the most frequently used. Arrived in the hands of the user as a dry powder to be mixed in water by the user. When used as scrimshaw ink on a protein based horn it will chemically bond to the surface of the horn. Not easily rubbed off since it is physically/chemically bonded to the horn. Since this ink forms an iron oxide tannate on the horn it will not fade as an organic dye would.
