What is the value of stamping ancient books?

Not only will it not affect the overall value of calligraphy and painting, but it will greatly improve its value. Because people who have the conditions to collect such masterpieces are often famous themselves, it is even more rare to have their collection records. At the same time, it can also prove that this work is carried out in an orderly cycle. For example, the famous Mid-Autumn Festival Sticker (written by Wang Xianzhi in Jin Dynasty) bears the seal of the royal collection: