It is best to print a postscript file to the disk and then use Adobe Acrobat Distiller to convert the postscript file to a PDF file. Be sure to use press, pre-press or High Resolution quality settings to ensure images will be Hi-Res. Always embed your fonts. Some programs can generate PDF files without having to print a file to disk and then use Adobe Acrobat Distiller. No matter which method you use to create the PDF file there are some basic rules to follow to create PDF files that will produce the highest quality output. 1. Always embed all fonts. 2. Use image files that are bitmap, grayscale, or CMYK, using RGB can result in color shifts. 3. In Photoshop, Tiffs must be flattened, in CMYK mode with no LZW compression. Do not save Photoshop files with halftone function or transfer function. 4. In Illustrator EPS, fonts must be outlined. Images must be embedded and in CMYK mode. Save the file as Illustrator EPS with Postscript Level 3 Flatten all transparencies. Select all objects and select flatten transparency from the menu. PDF proofs A PDF proof is what we call a soft proof because it is only viewed on your computer monitor. Because of variances in monitors, PDF proofs are not accurate to color. They are accurate to composition and trim size. If color is critical we strongly recommend a hard copy proof.