Who knows what transparent paper is called when practicing hard pen calligraphy?

Two kinds, the thin one is called carbon paper, and the thick one is called sulfuric acid paper. Generally, there are relatively large places to sell office supplies.

Sulfate paper is mainly used in printing and plate-making industry, which has the characteristics of pure paper, high strength, good transparency, no deformation, sun resistance, high temperature resistance and aging resistance, and is widely used in manual drawing, pen/inkjet CAD plotter, engineering electrostatic copying, laser printing, art printing, document recording and so on. There are 63gA4, 63gA3, 73gA4, 73gA3, 83gA4, 83gA3, 90gA4, 90gA3 and other specifications.