When printing from a digital source, sharpening is required for the most pleasing output. The technique we use may be familiar to anyone who uses Photoshop, but the degree to which we sharpen is often surprising. What you see on the screen is not what you see in printed media.
This is the original file, sized down and sharpened for screen viewing
Here is a 100% crop, unsharpened
Sharpened using Photoshop smart sharpen, 132%, radius 2.0 pixels
The crop sharpened for print output looks oversharpened. It almost looks cut out, with a sort of halo around the edges, when viewed at 100% as shown here. However, all of these artifacts disappear when printed. Part of the reason is most current monitors show around 100 pixels per inch, or ppi. This is like viewing under a 3X magnifying glass compared to printed output.
