Preparing Hi-Res PDF for Source Data Image Files
To create a PDF, choose "Save as" and from there "Save as type: Adobe PDF (*.PDF)".
Create the following new Adobe PDF Preset from the settings in the "Save Adobe PDF" box that appears:
First, select [Illustrator Default] from the options.
From the option on the left, choose "Compression"; for all options listed (Color Bitmap Images, Grayscale Bitmap Images, and Monochrome Bitmap Images), select "Do Not Downsample" and for "Compression" choose "None". Leave "Compress Text and Line Art" selected.
The name of the preset should now have "(Modified)" added to it.
You can save this preset for future use by clicking the download icon in the top right corner (circled in red in the image below). It will save as a new ".joboption" for use in all Adobe Creative Suite products. Note that this preset should not be used from within Photoshop. Please see our Photoshop-specific instructions.