This standard specifies a method for the determination of the average molecular weight and its distribution of film formation Resin for digital printing materials using gel permeation Chromatography (GPC). This method applies to film formation Resin prepared by the reaction of phenol, cresol, diphenol or mixtures thereof with formaldehyde. This method can determine Resin with an average weight average molecular weight in the range of 200040000, a data molecular weight of 5005000, and a distribution coefficient of 4.0 to 8.0. The standard provides detailed steps and calculation methods for separating polymer molecules by Chromatography Column and calculating the molecular weight and molecular weight distribution of the sample to be tested using a standard sample with known molecular weight.