Black bar detection method of PS (Presensitized Plate) substrate

The invention discloses a black bar detection method of a PS (Presensitized Plate) substrate. A PS substrate sample is washed with alkali, acid and water, electrolyzed and secondarily washed with alkali, acid and water sequentially, and the invisible black bar defect on the surface of the PS substrate can be showed. Therefore, the detection and the judgment of the black bar defect of the PS substrate are achieved. The detection judgment rate of the black bars of the substrate before leaving factory can be greatly improved, and the return of goods and the claim for damages caused by the black bar defect can be greatly decreased.