If you want to etch a PCB with a layout in Eagle then you will need to create an image like this one to transfer your design. This brief tutorial explains how to set things up so that you can use the Eagle export command.
Let’s say you are starting with this layout. This is Joe Davisson’s Antiquity Fuzz from his Analog Alchemy site.
First, change the background to white by entering the command “set palette white;” and then the command “window;” (or press function key F2 to refresh to the screen and see the change. I get this:
Next, display only the traces and pads by entering the command “display none bottom pad via;” to get something like this:
If you have any ground pour, remember to run the “ratsnest;” command. For this layout, I ran the GND polygon all the way around the board so that I get
Finally, enter “export image pcb.png monochrome 600” and you will create a .png format graphics file at 600DPI that looks like this
The file will have the name pcb.png and it will appear in the same subdirectory as your board file. You can print this file with MS Paint or insert it into MS Word and it will print to scale. This is true no matter what resolution you choose for your file. For example, 300DPI works well for PnP Blue transfers to copper clad boards.