What color paper was used for Spring Festival couplets in Qing Dynasty?

The Spring Festival couplets in the Qing court are written on white paper. During the Spring Festival of 2009, Xinhua News Agency interviewed Professor Wu Bin, President of Shenyang Palace Museum, and Tong Yue, Director of Research Office of Shenyang Palace Museum. Wu Bin said that during the New Year, people should stick up door gods and Spring Festival couplets, and the court of the Qing Dynasty was no exception. The difference is that the Royal Door Keepers and couplets are hung, not pasted. Spring Festival couplets are not written in red paper, but in white paper or white silk, with blue edges on the outside and red stripes embedded inside. Calligraphy was originally written in Manchu, and changed to Chinese characters after the middle of Qing Dynasty. The door gods hanging in the Qing palace are first framed with copper ornaments, painted on thick silk or cloth and edged with yellow silk. There are four kinds of door gods, namely, Golden Door God, Gu Wu Fengdeng Door God, Fushou Shuangquanxian Door God, and Boy Door God. Tong Yue, director of the research office of Shenyang Palace Museum, said that after the Qing Dynasty entered the customs, many Manchu folk customs were gradually brought to the court. The difference between the folk Chinese New Year and the palace is that the royal door gods and couplets are hung, not posted. Spring Festival couplets are written in white paper or white silk instead of red paper. The hanging time is from the 23rd of the twelfth lunar month to the 16th of the first month of last year.