imagePROGRAF PRO-1100 inconsistent print quality, now only bad quality

[AtticusD]

Hello!

I have loved my Pro-1100 printer until recently it started producing inconsistent print quality. Firstly, by "quality" I mean what appears to be the PPI is reduced. Printed images look grainy but there is no banding or color issues, just looks like I tried to print a low resolution file at too large of a size. Thing is, I get inconsistent quality printing the same image file with the same settings from the same application. Or at least this WAS happening, now it's stopped printing quality at all. We've gone from a random 1 out of every 5 prints being crisp and nice to absolutely none. It was a gradual transition to this point
Drivers are updated, computer OS is updated (mac OS Tahoe 26.3.1). Printer is connected via WiFi. None of the inks are low (at the beginning of this, now this troubleshooting is going to cost me a few hundred dollars...). I had been printing on Canon Premium Matte paper but have switched to plain paper for troubleshooting after it stopped producing quality. It has printed with best quality on plain paper in the past. The image I am using to test quality is a 98 MB TIFF, 3500 x 4600 pixels, 300 DPI, printed scaled on 8.5" x 11" paper. 
I have consistently selected the "best" or "fine" or other similar quality settings in the print dialogue throughout this troubleshooting. I can go into the details of the various available presets in each program I've printed from but they're all pretty similar. I have tested every iteration of the food quality settings to no avail. I had a tech-support friend help me troubleshoot and he went into system settings I didn't even know existed and played around with everything he could think of (although he's not a printer specialist) and none of it made a difference on quality.

Point is, I've tried everything I can think of and I can only get prints that look like they came from a home desktop printer from the 2000s. The photo I've included has the "best" quality on the left and what I'm getting now on the right, regardless of the settings I select. Also, hopefully it'll look better in the post, but the preview of this image I'm including looks bad because I had to reduce the file size significantly to include it here...

Please help

[SignifDigits]

Wow, sorry to hear about your issues.  The only thing I didn't see in your post was the application and/or applications you are printing from.  Are you using Easy-Photo Print Editor from the Canon support site at https://www.usa.canon.com/support/p/imageprograf-pro-1100  ?  If it were me, I would try the following, and I think in this order:

1) Blame the computer - uninstall all Canon SW and reinstall from the Master Setup (I'd try this first as I'm cheap).   I don't know about Macs but for Windows Canon SW sometimes leaves unwanted files, so removing the SW may take a "cleaner" or manually removing folders.

2) Blame the printer.  Make sure the firmware is up to date (no, I don't really think that's it, but I would still do it).  Run though all 3 levels of cleaning at https://support.usa.canon.com/kb/s/article/Clean-PH-PRO-1100  if and until the quality gets better. If cleaning works be sure you run a test page every week or so to ensure the ink stays moist in the heads.  These printers like to be used and you will use a LOT less ink with a weekly test print that running those cleanings.  I haven't done them, but understand they use a lot of ink, but often fix problems like yours.  Sorry for that bit of bad news 😞

3) If everything above failed I would call Cannon.

[AtticusD]

Oh gosh! I knew I was forgetting something. I have tried printing from Photoshop, Affinity, and Mac Preview. All of which were able to produce quality before. Would you recommend the Easy-Photo Print Editor?

I will try uninstalling and reinstalling, this is a good idea!

Firmware is up to date and this printer gets regular, weekly use minimum and if I haven't been using it near-daily I do a nozzle check page for the week. Still, I will go through the cleaning procedures for due diligence, at least I'll be able to tell Canon that I tried it!

Also, in the past 24 hrs racking my brain over this some more I remembered that about a month ago I lost WiFi connectivity for no apparent reason and had to disconnect and re-setup the network. I hadn't noticed any immediate issues after this but I can't say for certain because at the time I was only needing to print the "normal" quality. I've read that sometimes there can be data transfer issues when using WiFi and I do have my computer setup one room over from the printer. I'm thinking of getting a (very long) High-Speed USB cable to connect directly to the computer but even if that works it would be a pain in the ass. 

Thank you for all of your help!

[SignifDigits]

Sure thing.  For a true clean uninstall you might have to poke around and remove some files - I dunno for sure if this applies to your Mac.  Sorry, this was for Windows.  I Googled to find the info first time for Windows 11 so might be worth a double-check for the Mac uninstall.  https://community.usa.canon.com/t5/Printer-Software-Networking/Professional-Print-and-Layout-Canon-i...