When it comes to file preparation of large-format banner printing, there’s a different mode of thinking. The traditional rules of file dimension and resolution used in standard offset printing don’t necessarily apply. Where traditional print methods have you working in the 300-dpi (dots per inch) range, large format basically reverses that thinking altogether. This is where a number of traditional print designers and desktop publishers find themselves in unfamiliar territory. There’s a common misconception that bigger files need more resolution than normal print jobs—this is simply not true. All this does is give you a really huge file size.
Preparing files for Large Format Printing does not usually require the higher 300 dpi image files commonly associated with other printing methods. "Large" implies just that. 300 dpi images at large sizes can produce extremely large files - in the gigabytes range. This is usually not necessary and places extra burdens on all raster image processing systems (RIPs). You will find a wide range of opinions when researching this subject. When setting up images with the document size set at full size (the size of the printed product) it is only necessary to set the pixel size at 100 pixels/inch for most types of banners.