I'm working with a client that needs a number of large dye sublimation prints on aluminum. I'm trying to communicate with them the resolution I need to go that large and have my service bureau print the images. I found this calculator on line: http://www.photokaboom.com/photography/learn/printing/1_calculators.htm#Pixels For a 30x40 print at 300 dpi it says I need 9000 x 12000 pixels. Is that how I would communicate the resolution I need to my customer? I know that viewing distance plays into how high of a dpi you need. These are photos going into a factory setting and would be viewed from at least five feet away. Do I need 300dpi? What might you suggest? By the way, I know just enough to be dangerous here.