My Keynote templates have a master slide that helps me lay out the pages. I add a number of lines, dotted and light, that help me when I lay out a complicated page. They are regular lines which I place and use visually as a guide..I would like to make it so that those don't print. Is there a way?
Guides are the only non-printing elements in Keynote.
You can either use a duplicated set of masters (e.g. one master which includes your guide elements and one which doesn't). Then either manually switch masters before printing or delete the guide-elements master and replace with the non-guide-elements master.
Or you can insert "regular" guides (drag out from the rulers) on your master slides, then enable "View Master Guides" (Keynote View menu > Guides > View Master Guides) to show the guides from the Master slides on the "regular" slides.