Eagle CAD: PDF scaling problem? (tone transfer method)
I type in the command line of eagle.

DISPLAY NONE

DISPLAY BOTTOM PADS VIAS

EXPORT IMAGE C:\PathForImage\ImageName.PNG MONOCHROME 600

Then I do an invert in GIMP and print it.  It will be 600 DPI and the PNG seem to print correctly onto my label backing wax paper that I iron onto the board.