By now ediz has learned ruler markings on a easel don't mean a whole lot. Once again, what I'd do is make a mask on a drafting or light table with a t square, triangle, and exacto knife to lay on top of the print paper before closing the easel. Yes, it will be a bit of trial and error cutting your masking paper just right. but once you've made one, you're set. As long as you use that one brand of paper, logically all border will be straight and equal. After 58 years in the graphic arts and photography business, nothing is perfect till you MAKE it perfect. No easel at any price is going to give you that.