Reply #7: Actually it's anti-aliasing and it is a product of the scanning/sampling process

[Azathoth]

Most spatial sampling techniques employ some kind of anti-aliasing filter since the source resolution is always far higher than the sample resolution. I just looked at the original pdf, and both signatures are anti-aliased except for the last part of Dunham's. When you look at the rest of the document you can see why -- the sampling algorithm is apparently adaptive. The heavier and more uniform the text, the less anti-aliasing applied to the resulting sample. Thus, most of the printed words are heavily aliased (blocky), while the thin lines of the form and the pen strokes of the signatures are strongly anti-aliased.