The halftone scanning function in MOST scanning software is used for scanning art that has already been scanned and has a dot pattern. Scan at the right resolution.
Most new users scan at too high a resolution.
We capture too much detail it we scan at too high a resolution. Too high a resolution will create huge files and increase printing time. Plan before you scan. Know the size you want the halftone to be in the finished piece. If you plan to reduce the image 50 percent it will double the resolution.