grating vs unsharp

grating

adj
  • Abrasive; tending to annoy. 

  • Harsh and unpleasant. 

noun
  • An optical system of close equidistant and parallel lines or bars, especially lines ruled on a polished surface, used for producing spectra by diffraction. 

  • The strong wooden lattice used to cover a hatch, admitting light and air; also, a movable lattice used for the flooring of boats. 

  • A barrier that has parallel or crossed bars blocking a passage but admitting air. 

  • A frame of iron bars to hold a fire. 

  • The sound made by something that grates against something else. 

  • The loose material that comes from something being grated. 

unsharp

adj
  • dulled or intentionally blunt. 

  • out of focus; blurry. 

verb
  • To sharpen (an image) by creating a blurred ("unsharp") negative as a mask, and then combining that mask with the original. 

How often have the words grating and unsharp occurred in a corpus of books? (source: Google Ngram Viewer )