Marks and Bleeds
When making a low-res PDF I do not check the box marked “All printer’s marks,” as doing so invariably results in questions from the client. “What are all those little squares of color?” or “There are funny little lines near the corners!” To avoid these, it is usually better—whether making a file for the client, or to put on a website—to create a PDF of the final page area and nothing more. Therefore, bleeds and slug areas are also not normally included.
When making a high-res PDF for print, I always check the “All printer’s marks” box. Then, everything useful to the printer is included, especially the color bars. The printer can read the density of the pure CMYK tints in these (as well as a variety of other combinations) ...