Sorry but I'm trying to cover everything here because I have no idea what I'm looking for...
To create the PDF I'm using...
File / Adobe PDF Presets / Press Quality...
Standard = None, Compatibility = Acrobat 5 (PDF 1.4)
Then General = Optimise for Fast Web View, View PDF after exporting. Then Compression = Bicubic Downsampling to 300ppi for images above 450ppi, Automatic (JPEG) Tile size 128, Image Quality Maximum. The same settings for Greyscale Images. Monochrome Images = Bicubic Downsampling to 1200ppi for images above 1800ppi, Compression = CCITT Group 4, Compress Text & Line Art, Crop Image Data to Frames.
The usual marks, bleed and information.
Output = No Colour Conversion, Don't Include Profiles.
And the rest I don't touch.
Any ideas???