When using masking fluid, it is so important to paint it in accurately. It should be used as if it were paint. So often, one is tempted to "generalize" when using masking fluid. In this detailed view, the masking fluid is easily visible because it is tinted yellow. There is a masking fluid on the market which is clear, but I find this very difficult to use because I can't see it on the page. Masking fluid is used to mask out areas which must remain white or light such as the lion cub's whiskers and the "spark" in.