Quote Originally Posted by nworth View Post
.... For example, if you are shooting at f/8, diffraction limits you to about 200 l/mm; a document film like CMS 20 will give you about 250 l/mm; and a good lens for a medium format camera will probably be about 120 l/mm (maybe a bit more). Combined, this yields a resolution of about 95 l/mm, which gives a print resolution of 120 l/in - a quite noticeable degradation at an arms length viewing distance...
250 lp/mm ( line pairs/mm ) has been reached in format 120 and 135 at ƒ/5,6 white light diffraction limit.
400 lp/mm ( line pairs/mm ) has been reached in format 135 at ƒ/4 white light diffraction limit, Spur Orthopan UR / Adox CMS 20.

Resolution lost using decent APO enlarging lens is ~ 5%.
BW paper is not limiting factor.