Quote Originally Posted by Bill Burk View Post
But it is made of ink pigments.
Bill,

All colored objects that are not self-luminescent derive their color(s) from pigments.
The number thereof available in the printing industry is staggering.

Many of these are inorganic, and can exhibit very stable colors over centuries or millenia.
One recent example is a particular blue that was used by the Mayan culture in Central America 2000 years ago.
It is still as bright and vibrant as when it was originally mixed. The same is true of their red pigment.

The choice of specific pigment(s) to use for a particular application will take into account many factors.
When one is designing a standard, stability and longevity are top priorities. Macbeth did its homework.

- Leigh