Scanner is cutting off edges of scanned document but adding extra white margin as well

[usagora]

I've noticed an odd issue with the scanner on my MFP.  I have the scan set for letter-size (8.5 inch x 11 inch) original, but the PDF scan image adds an extra white border to the right edge and bottom edge.  Additionally, content on the edges of the original is cut off on all sides (some more than others).  The severity of these issues is higher when I used the ADF vs. the scanner glass, but they are present as well when using the scanner glass.  Additionally, the colors in the scan when using ADF are very washed out compared to the colors in the scan when using the scanner glass.

See the images below.  The first image is a photo I took of the original document, which in this case is a red letter-size 24-lb. paper with circles drawn touching each of the 4 edges for reference.  The second image is a screenshot of the pdf resulting from an ADF scan.  The third image is a screenshot of the pdf resulting from a scanner glass scan (flatbed) on the same printer.  What is causing 1. the edges to be cropped, 2. the extra white area to be added, and 3. the washed out colors when using the ADF?  Here is a link to the original images embedded below so you can download them and zoom in to see better if needed:

[3rd party link removed]

PHOTO OF ORIGINAL

ADF SCAN OF ORIGINAL

GLASS SCAN OF ORIGINAL

[usagora]

Anyone have any ideas what's causing the scanner to do this?  I'd really like to get this resolved!  Obviously using the scanner glass is not a solution for documents with lots of pages - and even the scanner glass is adding extra white space, just not nearly as much as the ADF (even though both are set for the same paper size: 8.5 x 11).

[usagora]

After more experimentation, it seems this is an issue with the PDF file format for scans, as when I changed it from PDF to JPEG, there were no extraneous white borders in the resulting JPEG file, even when scanning with the ADF. Of course, that doesn't help if I need to scan a multi-page document, as I would have to export a bunch of JPEGs to PDF and then combine them. Obviously impractical.

However, for some reason if I use the HP Easy Scan app to make the scan instead of the printer's control panel, I'm able to save to PDF without the extra white border. The HP Easy Scan app has a "Crop To" setting where you select the page size (A4, legal, letter, etc.) that seems to make this work. Why this isn't a setting available from the printer's control panel or on the printer's web interface, I have no idea.  Nor do I have any idea why this option would have a different effect than simply setting the proper source document page size, which I have indeed done in the web interface for my scan to network folder settings.

So I feel better knowing I can use the HP Easy Scan app to achieve the desired result, but it still bothers me that I can't achieve this result with walk-up scanning without having to open an app on my computer. If anyone has any clue why I'm getting white borders on just 2 sides of my PDF pages when scanning 8.5 x 11 letter-size documents from the printer control panel even though I have it set for 8.5 x 11 PLEASE let me know. It's really bugging me why the results are inconsistent with the other method (HP Easy Scan app) and also between the two file formats (PDF and JPEG).