The selection and function of cleaning water. The re-mounting of ancient and old calligraphy and paintings usually requires washing or soaking with water, as water can dissolve many substances and is the most important solvent. It can not only soften the paste, but also remove the dust and stains that have remained on the surface of the calligraphy and paintings due to their long age.
https://www.oilpaintingproducer.com
As for water, untreated water existing in nature often contains various microorganisms, organic matter, metal elements and soluble inorganic salts, etc., such as well water, river water, stream water, etc., which is not conducive to the protection of ancient calligraphy and paintings. The treated tap water we use in our daily life is acceptable for cleaning ordinary ancient and old calligraphy and paintings (it is cheap and easy to operate), but it is not ideal for cleaning collections of high value. In this case, we should use distilled water or purified water. Only such water can effectively protect high-end calligraphy and paintings. Washing or soaking ancient calligraphy and paintings in unheated water can keep the ink color, color and patina on the surface of the calligraphy and paintings basically in their original state (provided that the ink color and color do not fade in the first place). After re-mounting, the color of the calligraphy remains calm, but the drawback is that the decontamination power is weak. Usually, framers prefer to clean calligraphy and paintings with hot water (about 80℃). The most significant function of hot water is to quickly soften the old paste between the papers, making it easier to remove the paper from the center of the paper. At the same time, it has a strong cleaning power. However, for those lacking experience, using hot water, especially water with added chemicals (such as bleach powder), to clean paper paintings and calligraphy, if not handled carefully, can lead to excessive whitening of the Xuan paper, causing the paper to rot and lose its necessary tensile strength, resulting in rather serious consequences. Therefore, to properly handle the two issues of cleaning and soaking of ancient and old calligraphy and paintings, on the one hand, the effect of the cleaned pictures should meet certain standards; on the other hand, it should be conducive to protection. The water temperature selected should be between 40℃ and 50℃, and the time must also be controlled. Because if the time is too long, some side effects may occur, such as the picture becoming slippery and moldy, and there is even a risk of washing off the seals on the silk painting. It is particularly important to note that paper paintings and calligraphy made of gilded xuan paper must never be washed or soaked in water. Otherwise, the Xuan paper and the gold foil will separate, and the consequences will be irreparable. At present, the protection of Western-style paper cultural relics abroad generally adopts a series of processes such as PH value acid-base testing, acid removal, bleaching, and dechlorination. In the middle of each process, water is used for rinsing until the PH value reaches neutrality. These more advanced scientific methods should be studied and drawn upon by us.
The control of moisture when ancient calligraphy and paintings are covered on the back wall. Due to the inconsistent expansion and contraction rates of the core and inlay of ancient and old paintings and calligraphy after getting damp, it is difficult to cover the back. Take an old silk painting as an example. The following factors need to be considered: the paste used to support the core is generally thicker than that on paper. Before inlaying the material, the core of the painting needs to be pre-contracted. After inlaying the material, the back of the core of the painting needs to be folded into strips. In addition, the expansion rate of old silk when it gets damp is greater than that of paper, etc. If the center of the painting and the inlay are soaked in the same amount of water before covering the back, or if the water is too high, it will cause a distinct bulge in the center of the silk painting. When dealing with this type of painting, veteran framers usually adopt the dry back covering method. One of the purposes is to facilitate the control of moisture. Therefore, the amount of water before the painting is overlaid, that is, how to make the core of the painting and the inlay consistent in terms of expansion and contraction, is the prerequisite and key to the successful completion of the overlaying work.
After the painting and calligraphy are covered on the back and then put on the wall, it usually takes place in a natural environment. The humidity in the workshop is generally lower at the top than at the bottom (the opposite is true when using air conditioning). Therefore, the drying process of the entire painting begins in the sky. In this way, two problems arise: One is that the seams are not straight or even crack due to the imbalance in the drying process of the picture; One reason is that due to environmental factors, water spraying, and the amount of water contained in the material of the painting itself, the shrinkage of the painting during drying is inconsistent, that is, the overall internal force of the painting is unbalanced. The first problem can be solved by spraying some water to avoid the seams. The second issue requires humidification of the environment to make the painting damp on the wall again. This process should be repeated several times to gradually balance the internal forces of the painting and eventually achieve the requirement of a flat painting, which is what Zhou Jiazhou called "the longer the wall is left, the better it is, so as to fully experience the moisture and dryness of the weather."
https://www.oilpaintingproducer.com