Hi Peter,
The poster is originally in indesign with .eps images. I need to convert it to PDF to be printed for a conference. Viewing distance is probably 0.25 to 0.75 m away. I am seeing the pixelation ( I wouldn't exactly call it pixelation, more like fuzziness) when I blow the PDF up to 100% view of the 42x42 inch square.
I have attached an image to illustrate. 