wen worked originally in ivory, creating calligraphic designs that were incised into the material by his colleague li wenpu. however, after creating some experimental seals using soapstone, he switched to using stone for his work, and his later career focuses exclusively on this material. prior to this, seals had been carved from ivory, bronze or pottery. wen also developed the modern recipe for the red paste () used to create the seal's stamp; he recommended a mixture of ground cinnabar, castor oil and moxa. he zhen, founder of the huizhou (xingyuang) school of seal-engraving, was wen's student.