The brush tool is one of the most important tools in Photoshop, and it can be very frustrating when it doesn’t seem to be working correctly. There are a few possible reasons why the brush tool might not be working as expected.
One reason why the brush tool might not be working is that the wrong brush size is selected. The brush size can be changed by clicking on the drop-down menu in the options bar and selecting a different size.
If the wrong brush tip is selected, the brush tool will not work correctly. The brush tip can be changed by clicking on the drop-down menu in the options bar and selecting a different tip.
Another reason why the brush tool might not be working is that the wrong color is selected. The color can be changed by clicking on the color swatch in the options bar.
If the wrong blending mode is selected, the brush tool will not work correctly. The blending mode can be changed by clicking on the drop-down menu in the options bar and selecting a different mode.
If none of these reasons seem to be causing the problem, it is possible that there is a problem with the Photoshop installation itself. Uninstalling and then reinstalling Photoshop may fix the problem.