I can only answer with respect to copper cents as those are the only coins that I have in this album type. From what I have, the copper coins do not seem to tone much. Some of the cents are still very bright, though I am somewhat unsure if some of the darker ones had a little darkening from fingerprints or something before they were put into the album. The 1913 penny in the pictures below has been in this album a minimum of 50 years, and may have been longer. Several of the 1930's BU cents have some small dark spots. The storage condition for these has not been excessively hot and humid (Michigan), though also not climate controlled.

