How do you save PDF files to print on large format printers?

What specifically are you looking for?

In terms of page size, one option is to create original documents that match the final print size 1:1. This could lead to very large page sizes, sometimes exceeding the capabilities of some design applications.

Alternatively, many if not most large format printers have the ability to scale output such that an original 11x17 can become a 22x34 or 33x52 simply as a job submission option.

Image resolution depends on how close to the large format output the viewer is. 300dpi for very large pages requires images that are perhaps much higher than the original image can support. On the other hand, if a poster is going to be viewed from 10 to 20 feet away, high resolution is not necessary or appropriate.

In tems of color, many large format printers (especially inkjet) support more than just CMYK colorants such that more vibrant colors can be printed. It is best to leave digital imagery in its original ICC color managed RGB color spaces to take advantage of the wide gamut provided by these extra inks. Converting to CMYK in creating the PDF eliminates that possibility!

          - Dov