In terms of architecture, only 1/3 of the Forbidden City is open, and the remaining 2/3 is used for some office and closed arrangements. According to the specific conditions of different palaces, the open part will be arranged and maintained in small and individual places every year or at regular intervals, and large-scale internal and external renovation will be carried out according to different conditions. For example, the renovation of many palaces in the Forbidden City is of course a kind of protection and the main way, not all for the sake of looking better.
And now some steps and floor tiles are completely covered with things.
Specific work generally depends on different places, such as walls, beams, doors, windows, colored paintings, glass and so on. And there are different methods.
(The following content is taken from the website of the overhaul of ancient buildings in the Forbidden City. )
Specifically, there are three-dimensional laser scanning technology (for the construction drawings of ancient buildings in the Forbidden City)
-color painting: 1. Using digital image technology, the preservation status of color paintings of ancient buildings is truly and originally recorded. 2. Detailed investigation, recording, analysis and construction drawings of undisturbed diseases. 3. Adhere to the organic combination of traditional restoration technology and modern scientific and technological means. The cleaning of surface pollutants uses solvent materials, such as dough, deionized water and EDTA. 4. For partially hollowed-out and partially armored color paintings, the method of injection infiltration reinforcement is adopted. 5. For some color paintings with serious tendency of hollowing and falling off, we can take the method of uncovering and sticking and the measures of propping up, which not only strengthens the color painting itself, but also has little influence on the color painting. 6. Traditional techniques and materials should be used to make up for the defects of color painting, and the principle of harmony and identifiability should be followed in color effect. 7. SiOR-3 1 protective agent for color coating should be sealed and protected as a whole. The establishment and perfection of these methods have played a great role in the protection of colored paintings of ancient buildings in the Forbidden City. At the same time of color painting protection, in order to make a more scientific and systematic study of color painting pigments, we also made a preliminary study on the pigment composition and color standards of some different buildings.
-Glazed glass: For glazed components with different preservation conditions, we have studied the methods of glazing and re-firing glazed tiles, bonding and strengthening protection, polymer re-glazing protection, and weather resistance protection of silicone materials, so as to prepare for different protection objects and requirements.
Our institute cooperated with the World Architectural Heritage Protection Foundation of the United States to protect the scientific and technological protection achievements of the Lelante project as follows: 1. The physical and chemical indexes of traditional materials such as mulberry paper mounted on landscape painting were tested in detail, and the pH index of mulberry paper was determined according to the international pH standard of similar paper (acidic paper is not conducive to painting protection), and the detailed technical requirements for the processing technology of handmade paper were formulated. 2. By using modern methods and instruments, the indoor natural lighting index of tired Zhai Qin was tested and analyzed. The idea of imitating natural light lighting is preliminarily determined (the restoration of the light environment of ancient buildings is a famous problem in the field of architectural light environment, which should not only reproduce the original appearance of the light environment, but also avoid the damage of light to the indoor environment that has become a cultural relic, and how to weigh the advantages and disadvantages is the key to this kind of research). 3. Some traditional crafts involved in this project are special cases made by the royal family in those days, such as lattice fan on the edge of kang, bamboo silk collage and other geometric decorative patterns. There is no written record of this technological process, and we can only interpret (restore) this technological process by taking detailed photos, recording and looking for laws during the restoration process. 4. The investigation of indoor mold and the monitoring and analysis of indoor temperature and humidity provide scientific basis for the next environmental protection work.
-Sand blasting cleaning technology Our institute applies advanced sand blasting cleaning technology to the protection of stone and metal components of ancient buildings. According to the preservation status and surface pollution of stone components and metal components in the Forbidden City, combined with the protection project of Lingxiao Xuan (Crystal Palace) in Yan Xi Palace, on the basis of previous work, the working group chose the internationally advanced physical method of sandblasting to carry out experiments, and obtained safety and scientific data, which provided a basis for the implementation of ancient building components.