The term chromatography applies to a wide variety of separation techniques, based on the partitioning of a sample between a moving phase and a stationary phase. The invention of chromatography is generally credited to Tswett, who, in 1906 used a chalk column to separate pigments from green leaves. He referred to the process as chromatography because the term seemed to describe the colored zones moving through the column. Today, chromatography is recognized as the most powerful separation method with regard to resolution and versatility, having superior resolving power to centrifugation and ultrafiltration and capable of isolating larger quantities of protein than electrophoresis. Many different types of chromatographic methodologies have evolved, including paper, thin layer, and liquid chromatography.