I have a macOS Monterey and am scanning old photos into Photos to create a slideshow. Scanning the pictures from an HP printer. The photo quality is blurry and not usable...any help?

Glad to hear that it's working for you now. Here are a few tips for your ongoing scanning project.

• Scan in RGB (even b&w photos). Don't use greyscale or b&w for black and white originals; doing so will severely limit your ability to clean up and restore old photos.
• 600 ppi is a good target resolution for 4x6" and larger originals; it provides enough resolution data for cleaning up & editing old photos. At 600 ppi you can also enlarge the photo up to about 2x without losing quality for printing. 1200 ppi or higher is overkill for 4x6" and larger originals and just gives you larger files, not increased quality. (Unless you're doing museum work, in which case 1200 ppi is the accepted standard for archival scanning.)
• For originals smaller than 4x6" I generally scan at 1200 ppi because I usually want to enlarge the photos. 1200 ppi gives you the additional resolution needed to go up to about 4x, and perhaps larger, prints.
• All-in-one printers/scanners like your HP use CIS image sensors. The "C" stands for "contact" which means that the photos & documents that you scan must be completely flat on the glass of the scanner. If you have photos that are in frames or mats or are wrinkled the resulting images will not be in focus.

You'll want to check the resolution of your scanner. More dpi is generally better. You'll also want to check that your settings are set to photo as opposed to document.

Short of that, better scanners provide better quality.

There could be a number of reasons your photos are coming out blurred. More information will help.

What model HP all-in-one are you using?

What software are you using to scan?

What resolution are you using for your scans?

Are you scanning in RGB, grayscale or b&w?

Is the glass on your scanner clean?

Are the original photos clear (not fuzzy)?

Are the original photos completely flat on the glass of the scanner or are they wavy, creased or crumpled?

Or are they in any kind of mat or frame?

I purchased a flatbed scanner from Canon that does a very good job on photographs. In my experience, the scanners in all-in-one printers (print, scan, fax) don't give the best results.

I've also had excellent results photographing a print but this requires careful lighting and a good lens.

- Pie Lover