Quote Originally Posted by E. von Hoegh View Post
Stick some newsprint on a wall, about 20 feet away. Arrange it so you have small type in the center and edges of the frame, carefully focus, use a tripod, use several different apertures, etc.
That's the way I'd do it too although I usually work at shorter distances. You want to make sure your camera is plumb, level and square to the target too. I usually use a couple of string lines to set equal distance from the edges of the print. This is also a good method for squaring the camera to art work you're photographing for reproduction. Having a bubble level in the accessory shoe on your camera is really helpful too.

I take multiple shots at close range, medium and infinity keeping notes as to where the camera is set and bracket the exposures 1/2 stop either side.
Look at the negs with a strong loupe not the finished prints.
Mark