GB/T 1733-1993 "Test Method for Water Resistance of Paint Films" specifies three test methods for determining the water resistance of paint films: immersion in water, immersion in boiling water, and exposure after water immersion. These methods are applicable to various types of color paints and varnish films. The immersion method involves soaking the test panel in distilled water and periodically observing changes in appearance, while the boiling water immersion method focuses on the film's tolerance to high-temperature water environments. The testing requires instruments such as a constant-temperature water bath, glass water tank, paint film thickness gauge, and magnifying glass, providing standardized means for evaluating the water resistance of paint films.