Other options

Sharpening

Images produced by scanners are often slightly out of focus, with or without dithering removal. Fortunately, scanner interfaces include a filter to accentuate image sharpness. This filter may be called Reinforcement, Clearer, Accentuate, Sharpen or Unsharp Masking.

Automatic correction

Most scanner interfaces also include a function for automatic exposure correction, normally presented as a checkbox. This function can even "save" photos that are too dark or too light.