Preparing enlargements of raw pictures for professional printing?

Question

If one is having large prints made by a professional printer (say, 3' square or more), does one... (1) ...take care of the enlargement in Photoshop (upsampling to necessary dpi in raw before outputting to tiff)? (I'm using CS6.) Or... (2) ...give the printer the photoshop file with the raw image in it? Or... (3) ...something else? Thanks to you all, as always!

Answer 1

Large format prints don't need as many pixels per inch as a smaller print because they are meant to be seen from afar. Therefore, you don't need to worry much about loosing quality when enlarging your file. Ask the printer which size, resolution, and color mode they require for the job and save the RAW file as a tiff or jpeg with those specifications.