How is restoration work done today?

In the past, the Palace Museum has been criticized for over-restoring parts of the Forbidden City, but I hear that things are changing for the better. How is restoration work done today?

In the Ci Ning Gong Garden, for example, where the concubines used to live, the color of the original [yellow-glazed terracotta] roof tiles had faded, so they were sent to a factory to be colorized. When the construction work on the rest of the building is finished, they will be placed back. All the tiles are the originals as they are of really high quality so we still use them. We also make brand-new ones, if necessary, when the originals are broken. But if the originals can be reused, we keep them.