I upgraded from DTP 1.5 to DTPO 2 specifically for the “Convert to searchable PDF” feature. I have lots of image-only scanned text PDFs that I want to be able to search over. The images in my image-only PDFs are low resolution (72 DPI), and low bit depth (1 bit, full black or full white), thus, they take up very little disk space, typically around 100kb/page. After converting to searchable PDF, I find that the file size increases to around 800kb - 1Mb / page to get equivalently readable results. It appears that the new image is saved at a higher bit depth than the original as high magnification reveals several shades of gray around letters. It seems a waste of resources to convert a black/white original into shades of gray.
In addition to the current resolution and quality controls for converting PDF images, I would also like control over bit depth.