Ebony and ivory.
Go back in time and you’ll find pianos made from things readily found in nature. And for pianos made before the 1930s, that included ivory for the keys. Ivory worked. It worked very well. Pianists will tell you that ivory keys are better to the touch, more responsive, and less likely to stick to one’s fingers. Ivory absorbs sweat, which provides for a better feel of the instrument while you play.
But ivory has its problems. It’s susceptible to chipping and cracking. It is vulnerable to yellowing. And most importantly of all, it may be illegal.
Plastic keys were introduced around 1929 when plastic technology began to improve. Plastics are easier to work with, less prone to damage, and cheaper to use in production. And right around the Great Depression, making things cheaper became a way of life.
Very quickly plastic keys overtook production of ivory, and they became the norm in piano key assembly.
Plastic maintains a stronghold as the material of choice in piano key production today. Resins are also used as an alternative to plastics, with an advantage being that they are more resistant to cracking, chipping or yellowing than their plastic counterparts. Even today, you’ll find both plastic and resin keys prone to “crescent moon” chips that form at the end of the key, especially with repeated abuse. And if cheap plastic keys yellow, there is no easy way to remedy the problem.
If you have an older piano and are trying to tell what the keys are made from, there is an easy way to tell.
Some plastics imitate ivory very well. You’ll see similar veins on the surface, with a comparable luster and feel. However, ivory keys differ in one distinct way. Ivory keys are made in three pieces, key, stem, and front. Plastic key tops only have two, top and front. If you look closely at the keys, you can see a fine line that is the joint between the key top and the stem. If this line is present, your keys are ivory.
