Ronald Moravec , Jan 11, 2008; 11:38 a.m.
The ways you get vignetting are improperly placed lamps in relation to the condensers or condenser sets being too small a diameter for the negative size, If you have proper condensers and enough of the are exposed to the full neg is exposed, there should be no vignetting. It does not matter if the corners of the condenser is cut off so long as the full neg is exposed. Check to make sure nothing blocks the light in the 6x6 area.
If the bellows is long enough to focus the longer lens for small pics, that will be ok.
Either 75 or 80mm lenses will work. Most better quality lenses are 80.
A quality 23C or other med format enlarger would be a better investment. The printmaker is strictly an amateur machine built to the lowest possible function standard.