I have a large (600+) page book that currently exists as an Indesign layout as well as an exported hi-res print-ready PDF. I'm trying to find the best (re: easiest) way to turn this into a lower-res, screen-ready PDF, using any combination of Adobe CC tools that might be best.
The entire book has embedded full-page illustrations that are very high res (2400 ppi) bitmaps. In order for them to look best on screen, I'm trying to convert these images to grayscale and then downsample (using bicubic) to 300 ppi instead.
What's the most efficient way to do this? I've tried my old method (making a copy of the image folder and Photoshop scripting the conversion, then outputting a new PDF in Indesign) but it's not working in this case, as the new grayscale images don't have transparency like the bitmaps and are thus blocking important layout items (page numbers etc)/
So -- is there a way to do this wthin Acrobat? OR perhaps another program?