All That Glitters

Someone suggested an intriguing possibility that I hadn't ever thought of (something, I will admit, that is probably of more interest to me than most of the people who will read this) ― the metallic gold ink used in printing might begin to tarnish with age!

I'd never heard of such a phenomenon before, but a cursory Google search did yield a document that refers to metallic ink "tarnishing due to contact with atmospheric pollutants, acids, alkalis etc." (Apparently, Pantone metallic inks have to be handled and stored much more carefully because of this.) I suspect what happens is as the paper has ages, the pH changes (it probably becomes more acidic with time), and this is the inevitable result.

Then again, I've seen several copies of a book published in 1948 that had significant gold detail on the dust jacket, and none of them displayed any evidence of this sort of problem. Granted, that was about 15 years before Pantone inks were introduced (I'm not sure when Pantone's metallic inks were first used), but I would imagine the underlying composition of the ink is more or less the same.

My (very) small publishing company reissued this book as a replica of the original edition, a few years ago. I wonder if my edition will have that same longevity?