Whether there is oil leakage. Whether oil seeps or not is the basic feature that distinguishes calligraphy and painting inkpad from ordinary office inkpad, which needs to be compared by observing ink shedding. In fact, there is absolutely no oily inkpad, especially when it is hot in summer. However, the stamp pad of calligraphy and painting cannot have obvious extravasation and bleeding at the same time, otherwise it is not available.
Dry and wet. Generally speaking, small seal script should be dry, seal engraving should be dry, big seal script should be wet, Chinese painting should be wet, and calligraphy should be moderate. This dryness is relative and can be judged by the hardness of the touch when buying (basically, different batches of the same variety of inkpad will have differences in dryness and wetness).
Big and small. Because the specific gravity of cinnabar is 8 times that of water, and the specific gravity of general pigments is much smaller, pure cinnabar or cinnabar with higher specific gravity is smaller under the same weight.
Brightness. Most of the ink is red. Real pure cinnabar ink is not as bright as synthetic pigment, so you can pay attention to the contrast. Pure cinnabar inkpad, regardless of color depth, is very complicated, that is, it feels like the superposition of several colors, while those with synthetic pigments or pure synthetic pigments are monotonous. The characteristic of cinnabar is that its color can last for a long time, and it is not very bright.
Shielding, the wok is covered with ink, and the excellent inkpad has good shielding power. Put the paper under strong light, even if the inkpad is red, the impression you see is dark gray, which is opaque because of its good shielding.
Printing reducibility. The same seal has been stamped repeatedly for many times. Compared with the seal, the deformation of good inkpad is small, and the difference between stamped inkpad and seal is small. In particular, the inkpad used in seal cutting creation needs special emphasis on the reducibility of the seal, otherwise the level of creation in the early stage may be discounted. In particular, Zhu Yuanhe's engraving type needs to be more accurate about the edge marks of the seal. If the seal mud is distorted, it will not reflect the original taste.
Gloss. It is not good to be particularly shiny or dull. The former has faster oil film speed or too much oil pollution, while the latter will not print clearly.
Other problems often mentioned, such as sticking hair and pulling out mud bundles, are related to the mixing and curing time of inkpad, and cannot be used as a standard to evaluate the quality of newly bought or insufficiently cured inkpad. The drying speed is not necessarily related to the quality of inkpad, especially on Xuan paper, because the drying of inkpad is carried out at the same time with infiltration (fiber permeates into the paper, but not extravasation) and conjunctival oxidation, so the drying speed of different varieties is similar, but on relatively compact office paper, some varieties may be slow because of different oil-making processes, but the formula of inkpad for painting and calligraphy is generally aimed at Xuan paper.
In addition, we should pay attention to the color visual effect of inkpad. The mud color of inkpad is not necessarily the same as that of mildew. Generally, the color of mildew is slightly darker than that of mud. The color of the same inkpad on different papers (or other media) will also be different due to light reflection and media organization. As a special semi-fluid, the hardness of inkpad after standing will be different from that after continuous use. However, under the temperature difference between winter and summer, the hardness and adhesion of all inkpad varieties will be different, but the degree is different, but a small change is not necessarily good, because if one of the indicators of inkpad is strengthened, the others may be weakened, so we must compare them flexibly.