The finished scratchboard rendering is 200 percent (twice as large as the final print size) of the final print size. It will be scanned at 600ppi and at actual size. Later the image can be changed to the print size (half size) without resampling, making the resolution 1200ppi.

The image is scanned in Grayscale mode rather than "Line Art" (Bitmap mode). This allows the image to be adjusted (Levels, Unsharp mask, Threshold) before converting it to Bitmap mode, giving a much better result for the final line art image.

After the image has been converted from Grayscale to Bitmap mode, which removes all shades of gray leaving only black or white pixels, it is converted back to Grayscale. WHY?! . . . It was just in Grayscale before you changed it to Bitmap—your thinking. Because other pieces are going to be added to it and they need to be on layers. You can't have layers in Bitmap mode.