Just speaking to another 'designer' about some file size issues. We are printing some banners for their company and we recommended that the files be 48" x 24" at 100ppi (if raster files) to get a decent print at this size.
She has the graphic, bu it's 4x4" at 300ppi.
Her: "Can you make it bigger, so that it still looks good at that size?"
Me: "Well we can uprez it, but it'll be pretty blurry increasing it that much"
Her: "Can you print it out huge and then scan it back in at like 1200dpi?"
Me: (Thinking "wtf?! she's the designer?") "Ahhhh, no that wont work"
Her: "Well we had this other printer and I gave him really tiny files and he blew them up to 8 feet and they looked flawless! But he had expensive printers and was using a different method than you"
Me: "Unless he was using a vector file, I'm not sure how he could end up with the print looking any good at that size."
Her: "Well he did."
Me: "Ok then...." (thinking: "Look, you make a 'print graphic' at 4" wide and don't know what the difference between dpi and ppi is, how the jingo would you know if it was blurry or not?")
Her: "Can you put it into illustrator and scale it up in there?"
Me: "Well yes you can, but you wont gain anything over just uprezzing it in photoshop; it'll still be blurry."
I have a feeling we'll be getting a horribly uprezed file pretty soon...