How do I set a opacity level for printing? I am making a color area overlay on a drawing and I want to shade the sections of the drawing for output, but I can not figure out how to make the section colors a lite opacity to where you can see the drawing under it. Can anybody help me out with this

You could hatch a light solid color of your choosing & then send it to the back of the drawing so the lines show above & then change the color of the lines to be only slightly darker than the hatch.