I'm not sure that all color deteriorates over time. I guess that some forms of protection, other than a lacquer covering, prevents most fading.
I'm not either, Bill, and I am even more skeptical that light causes "case colors" to deteriorate or fade. My reasoning is that, due to microscopic evaluations of case hardened surfaces (iron oxides) it was learned many years ago that the colors themselves are only reflections of light from tiny iron oxide globules that are formed on the surface during the process. As Oscar put it, quote, "The predominant effect of the globules is probably their acting as miniature lenses and prisms which diffuse the reflected light in all directions, and the color is determined primarily by the thin continuous oxide film on the surface of the steel."
So, my reasoning is that if indeed the colors are due to a physical property, i.e. the configurations of the surface of the steel, how can light change those configurations? I cannot see how it is possible. I have considered the damage caused to many compounds by ultraviolet light, something that is real and quantifiable, but I cannot see how UV could change the physical properties of the surface of steel.
Now, I
can accept that oxygen plus humidity could do so, even wear from handling or cleaning, but light itself? Nah. Howevah', I am open to reason, and know that there may be things I have not considered.
SRH
