Use Photoshop only for creating and editing your high-res images to be included in Illustrator or InDesign.
NO text, etc. should be supplied in Photoshop; please use Illustrator or InDesign.
Save high-res images (4 color process or grayscale b/w) in CMYK, not RGB mode. Embed or place file in Illustrator or InDesign.
Save CMYK images no lower than 300 dpi at 100% size.
