In learning to use SideCar my iMac screen went very dark and I can

Hello phivot,

We suggest checking your display settings in:

1. Apple menu
2. System Preferences
3. Displays

Checking the display brightness, color, and Night Shift settings might help resolve the issue of your iMac display turning darker than expected. These steps and more can be found here:

Use an iPad as a second display for a Mac

For additional options, check out:

Change Displays preferences on Mac

Kind regards.

phivot,

Thanks for replying back. We’re happy to see that your concern is resolved.

Have a great rest of your day or evening.