It can be traced back to15th century. It is a traditional European painting technique before19th century. Transparent painting is mainly to cover the color and let the two colors produce a third color through visual harmony. Although it has the same hue as the third color derived from physical harmony, the visual effect is different. The former is deeper and has a jewel-like luster. In the process of using transparent painting, the sketch relationship of a painting is completed without using color. The so-called no color means to determine the composition and the sense of volume of the object in the form of monochrome and high-profile. Then, add a transparent thin color or light color to the color.

Transparent painting:

(1) transparent color reproduction. Generally, the background and dark part of the main object are painted with oil paint without powder or less powder to reveal the fabric pattern and background color.

(2) Transparent cover color and thin bottom. Draw a rigorous plain oil painting in dark brown or silver gray on a grayish brown background with intermediate tones, and cover it with transparent color after drying. Avoid adding too much white to the transparent color, so as not to affect the transparency. Therefore, the plain oil painting of the base painting needs to improve the brightness in advance, leaving room for multi-layer cover color.

(3) Thick bottom transparent cover color. Refers to the transparent color on glossy surface with thick background and the concave-convex surface with thick background. Thick coating smooth surface refers to smoothing with thick color before drying, and covering with transparent color after drying. This method is mostly used in classical oil painting. For example, the light-receiving part of skin is usually coated with thick pigment to separate it from the thickness of dark parts (such as background). When the thick paint is not dry, lightly brush the strokes to smooth it evenly, and then cover it with transparent color after it is dry, which can achieve a thick and transparent effect.

"Optical grey" is a visual effect of transparent painting. Ancient artists used resin varnish to glaze Tampere or oily background, and then coated with transparent or translucent covering layers, so that each color layer was overlapped and exposed, that is, the "optical gray" with strange color was produced. Compared with mixed gray, this transparent gray has different visual effects. It is impossible to draw directly. Rubens was famous for creating optical ash at that time. He once said to his students, "At least the last layer of color in the darkness should be transparent.