My perfect Fuchs!

Between 1880 and 1929, many 15th to 19th century books were colored for collectors.

Great wealth was created then and Fuchs were colored to "create" something appealing to new collectors.   That is why the estimate can be so low.  The auctioineer will  strongly telegraphe her feelings with a valuation far lower than a "right" example of this book.  

The easiest way to tell color that is 16th century is the oxidation of the copper in the green pigment that slowly burns through the paper (cuprous oxide and then cupric oxide after a valence is lost.)  Newer color bleeds through.  Examples can be shown to you on your next visit. 

This would possibly be ok were it not for the spotting or splotching caused by the unravelled cellulose fiber that results in a surface that is  unequally absorbent when the color is applied.   When you understand this it is easy to see because you know what to look for.   In the end it just looks terrible because it is "spotty"

That is why it is my feeling that my Fuchs is truly the finest example that exists because the oxidation is perfect.  It is what the author and publisher wanted.   It is a masterpiece because it is true