Scanning signature is prone to problems such as blurred image, irregular noise and long dark line, which Photoshop can handle.

1. Open the scanned image file in Photoshop.

2. Use a brush, choose a background color, and cover up the big noise.

3. Image-Adjust-Color Scale, adjust the color scale button to achieve the effect of black and white.

For a blurred image, you can use Filter-Sharpen-USM Sharpen, which may make the blurred image appear clearer.