First of all, we must distinguish the difference between white cloth and filler.
In terms of the art of calligraphy, white cloth is very particular. In layman's terms, cloth white means "leaving blank space", just like painting a portrait. Only by leaving a suitable blank space between the facial features can the person be drawn like the other person. If the facial features are together or too far apart, it will not look like the person. Like a painting". Calligraphy cannot be modified, and you cannot regret writing it. You need to "know exactly where the stroke is going to be." After a piece of writing is finished, the density and density are consistent, and the "organism" is formed.
The so-called "filler" is a kind of rescue after the fact. Strictly speaking, it cannot be said to be the art of calligraphy. For example, if the facial features of a portrait are not correctly positioned and one side of the face is too big, no matter how much shadow is added, the original flaws cannot be covered up.
For example: whitening refers to the correctness of the innate facial features, while filler refers to acquired makeup.
The painting "Quick Snow and Clear Tie" you gave is a calligraphy work by the calligrapher Wang Xizhi of the Jin Dynasty, but it is not an original work. It was copied by people from the Tang Dynasty. Judging from the composition of the entire painting, the final inscription "Shanyin Zhanghou" is very dazzling. It is too low, too large and remote, resulting in too much white space. Many people believe that the four characters "Zhanghou of Shanyin" are inconsistent with the writing style of the main text, or were added by later generations, or were claimed by copyists. Some people also believe that "Zhanghou of Shanyin" is the addressee and is a title of address, so it does not belong to the overall composition of the work. No matter what, "Shanyin Zhanghou" influenced the composition of the entire work, so later generations would add multiple seals to "fill in the blanks".
Compare the two pictures below,
The one without padding:
At the beginning, I considered the one with white padding: ("Sanyin Zhanghou" font unchanged, still uncoordinated)