GB/T 21557-2008 "Determination of Stickies in Waste Paper" specifies two test methods: the visual method and the image analysis method, with the latter serving as the arbitration method. It is applicable to all types of waste paper. By disintegrating and screening to separate stickies, the visual method involves direct counting, while the image analysis method utilizes an image analysis system for quantification. The standard defines the operational procedures and result calculations to ensure the accuracy of stickies detection in waste paper recycling.