Another obvious clue is that the collection was printed by the royal court. In the Northern Song Dynasty, Song Huizong had a set of collection seals, which were attached to the fixed positions of calligraphy and painting. These seven seals are: Imperial Book Gourd Seal, Shuanglong Square Seal or Round Seal, Xuanhe Square Seal, Xuanhe Square Seal, Zhenghe or Zhenghe Square Seal, Daguan Square Seal and Inner Seal. The above seven seals are all Zhu Wen. The world calls it "Xuanhe Seven Seals". Where there are these seven seals, they are in Xuanhe original frame format. Due to the age, most of the paintings and calligraphy works collected by Xuanhe Neifu were re-mounted by later generations, so it is difficult to keep them as they are.
However, collecting seals, like painters' seals, is not necessarily reliable. Since future generations can forge with the painter's seal, they will naturally forge with the collector's seal. The more famous collectors' seals are printed, the more imitations there are. I don't know how many times stamps like "Teana Pavilion" have been engraved. What's more, the appreciation and judgment of ancient collectors are always limited. Even if it is really his collection and the seal of the clock is real, what is missing is the original. Today's calligraphy and painting appraisal still needs our comprehensive analysis and investigation, and we can't just rely on Tibetan seals to determine the authenticity.
According to documents, during the reign of Emperor Wu of the Han Dynasty, a special institution was set up to collect calligraphy and famous paintings. The collection stamps used by the imperial collection agencies in the Tang Dynasty are Zhenguan, Kaiyuan and Yuanhe Seal. And the name of the collection place is printed with "Hanlin Seal" and "Hong Wen Seal". During the Five Dynasties, the books in the Inner Hall of the Southern Tang Dynasty were printed with the words "Imperial Seal of Jixian Academy", "Seal of Jianye Learning Room" and "Inner Covenant". During the Northern Song Dynasty, Hui Zong Palace had a rich collection of books and a complete system. Collect Tibetan works of art and record them into books "Xuan He Shu Pu" and "Xuan He Hua Pu". In the Southern Song Dynasty, the seals of the Emperor Gaozong's Inner Temple are: Dry Hanging Wen Yuan Yin, Xi Shi Cang, Shaoxing, Rui Dong Si Si, Inner Temple Book Seal and Inner Temple Book. Zhang Zong Neifu Collection in Jin Dynasty includes Secret House, Mingchang, Mingchang Palace Opera, Imperial Palace Painting, Imperial Palace Book, Leisure Time and Leisure Time Seal. The collection of Yuan Dynasty is printed with "Sister Huang's Book", "Sister Huang's Treasure", "Treasure of Calendar" and "Calendar". In the early Ming Dynasty, Hong Wunian's Collection of Royal Paintings and Calligraphy combined archiving and calligraphy and painting works into one: "seal for courtesy and discipline inspection", which is called "half seal". Emperors in the Qing Dynasty all had seals. The Forbidden City collects ancient precious paintings and calligraphy, and matches them with the emperor's treasures, or stores ancient paintings and calligraphy works in the palace name seal. Private collectors in the past dynasties generally have many seals, including names, posthumous title, names of Zhaitang, poems and Kyrgyz seals, as well as words that have been appreciated, read and appreciated. Although the seals of public and private collections do not have the function of sealing letters, they can understand the circulation of calligraphy and painting works, especially some collectors are contemporary with painters and painters, and some collectors have a high level of appreciation. Their collection is of reference value for understanding the content, form and authenticity of their works.