What do you think of my sample at #9?
I’d say that the black and white scan is a very high resolution scan and probably is first generation with little to no “lossy” compression resulting in a very crisp, clean, very legible birth certificate.
I think the Obama birth certificate was scanned by someone not overly concerned with resolution or compression and the degradation of the image. Add the fact that the final version we got today is probably 3rd or 4th generation and you have a very compressed-looking image.