I am trying to export a high res file. I have the canvas set for 1500x400, because that is as wide as I can make it on my screen and still see the entire board. Is there a way to make the canvas pixels higher, but minimize it on the screen so you can see the entire canvas? When I click "Export" there is no option to change the DPI. I need 300 DPI. How do you set this? Currently my logo exports at such bad quality my printer will not print it on a bumper sticker. Please help.