I've got the same problem.. It wasn't always like this but has been so for awhile. I just don't have time to maneuver the complicated user account sign-in community forum to report it.
I have been using an old Brother MFC-7820N for 11 years.. Been working great until I broke the hinge on the ADF recently.. Just setup a new HP Color LJ Pro M281fpw and it has the same exact problem.. I hit the "PDF From Scanner" button from Nitro's PDF menu and I get a poor quality scan.. I create a profile with the exact same scan settings as the default and it works fine. I get a nice quality scan but I have to open the PDF menu and choose the profile every time.. This is too time consuming.
I would like to know how to adjust the default scan profile settings.. 99% of the scanning I do is grayscale, 300dpi so I need to set the default scan to do this.. This wasn't a problem in earlier version of Nitro Pro but since upgrading to 11 or since the interface was changed to resemble a Microsoft Office ribbon bar it's been a pain in the butt to use for scanning.
Where do I change the settings for the default scan profile? If I can't fix this I'm going to search for alternate software for scanning. I've been a Nitro Pro user for 15 years. I've uninstalled and reinstalled NitroPro and it doesn't address the problem.
Nitro 11.0.7.411
Bryan