|| If humidity is too high, in addition to mould and mildew, moisture can also cause swelling which may cause the lacquered finish on some artifacts to crack or "craze". This cracking to the surface is also caused by the humidity being too low, and the leather shrinks. |
The cracking of the surface lacquer is known as "crazing" and is a result of old age. The original surface covering on spiked helmets was lacquer which being a derivative of the Lac bug is amazingly flexible. Poor storage, however, over many decades places the helmet at the mercy of the humidity rising and falling according to the season and temperature. This results in the leather shell expanding or shrinking accordingly. Years of this is reflected in the crazing of the lacquered finish on the surface. Obviously the only way to control this damaging action is to store the artifact in a stabilized environment.