Hi! Thanks for posting in the Canon Community Forum. I see that you are unable to find the color options for your Canon PIXMA TR8520 on a computer that is running MacOS Catalina Ver. 10.15.5.
Our older models did come with come with their own Mac drivers. However, our newer models have conformed to the Mac Standard known as AirPrint. AirPrint can be used to add the TR8520 (TR8500 series) to your computer. You will not be able to find a Canon driver because there is no need for one.
Other things have changed for these newer models. When you use AirPrint, you will not see a see an option that allows you to manage the color intensity. You may be able to manage your colors with other programs. For example, you can use Adobe Photoshop to manage the colors of your photos.
Since you mention that the colors are faint, I recommend troubleshooting the printer. If you have not done so, please print a nozzle check pattern. You’ll find instructions in the online manual. Here is a link:
You’ll find an example of a good pattern here:
For the Cyan < C > and Magenta < M > inks, there should be two bars of different intensity. The top bar should be the darker of the two and the low bar should be the lighter. If you do not see a difference in intensity for the bars, I recommend that you clean the print head nozzles. The instructions are in the following section of the manual:
If any of the color bars are missing, you should consider performing a deep cleaning instead of a cleaning. After the cleaning or deep cleaning, I recommend printing another test pattern. If there is no improvement, you should wait 8-12 hours and then do another cleaning. During that time, the ink may soak through the dry nozzles and loosen the clog.
Should you want to know what options you do have on a Mac computer using AirPrint, please visit the following page:
If you do not have your own photo printing applications, I recommend downloading and using the Easy-PhotoPrint Editor or My Image Garden programs. Both can be downloaded from the Canon Website:
You’ll find instructions for using My Image Garden in the following section of the manual:
For a guide to Easy-PhotoPrint Editor, please visit:
I hope this information helps. Thanks for choosing Canon.