Yuan master Huang Gongwang from the 14th century said: In painting there are four qualities that must be absolutely expelled: perversity, sweetness, vulgarity, and derivativeness.
This was at time when many scholars retreated from public office and lived in retirement under the foreign domination of the Mongols. They took refuge in the arts. What a nice idea.
Meanwhile a couple of centuries later the Mustard Seed Garden Manual of Painting continued with its lessons.
Here is a method for rendering a cloud hovering over a waterfall and partly hiding it.
| Wang An-Chieh, clouds and rocks, ~1680s |
In painting waterfalls, the ancients often used a device called yün suo (cloud lock), by which a cloud partly submerges the waterfall. In painting the cloud, one must be careful not to show any trace of brush or ink.
Both to reveal and to conceal.