I'm creating a layout with illustrator to print and the end result is 10'x10'. I need to save it as a PDF. The problem is, when i open the PDF in Photoshop, it opens at 300dpi and is incredibly unwieldy for my client and the printer and everyone involved. (I dont know why they cant just bypass Ps and use the Ai PDF as is, but apparently thats the case) So I'm being asked to save my PDF from Ai at 150 dpi. So that when its openned in Ps it doesnt take so long etc. How does one do that?