Attached Link: http://www.scantips.com/no72dpi.html

Actually, dpi or ppi or whatever you want to call it is meaningless on a computer screen. A computer screen displays x number of pixels in the width by x number of pixels in the height. Video cards and monitors don't know anything about dpi, just the width by the height. This is still one of the things that causes the most confusion among people doing computer graphics. Unfortunately it's not helped by some people who should know better (magazine writers, software reviewers, etc) saying things like Macs have a screen resolution of 96 dpi while PCs have a resolution of 72 dpi. That is just plain wrong. Change your renders from 72 dpi to 600 dpi. You won't notice any difference. This will only make a difference when you print them out. The 600 dpi will print a lot smaller than the 72 dpi image. Have a look at the attached link for an even more detailed explanation of why the whole dpi thing is just not relevant to a computer screen. On the sharpening side of things, one thing you can do in PSP is to split the image into channels (HSL) and do your sharpening (use unsharp mask)on the Lightness channel. This is better than using contrast and brightness or the plain sharpening filter, because it won't affect your colours. Then recombine the channels and you should have a much nicer looking result. Using this method seems to give much more latitude when sharpening, too. You seem to be able to be a bit more aggressive on the sharpening doing it this way.