Hi there! I see you're having trouble with the Zen Color app showing a black screen on your Mac running OS X 10.15.7. Let's work through this together.

Just to clarify:
- Is the app launching and then turning completely black, or does it fail to open at all?
- Have you recently updated the app or your Mac OS?
- Did you try restarting your computer or the app already?

Meanwhile, here are some steps we can try to get the app working again:

1. Restart the Mac: Sometimes a simple reboot can clear temporary glitches.

2. Force quit and reopen the app:
- Press Cmd + Option + Esc, select Zen Color from the list, and click "Force Quit."
- Then reopen the app to see if the screen displays correctly.

3. Check for app updates:
- Visit the official Zen Color website or Mac App Store to ensure you’re running the latest version. Updates can fix bugs causing black screens.

4. Clear app cache or preferences:
- Sometimes corrupted settings cause display issues. You can try deleting preference files related to Zen Color, typically under ~/Library/Preferences/. Look for files named like com.zencolor.app.plist and move them to the Trash (make a backup first, just in case). Then restart the app.

5. Check screen settings and permissions:
- Ensure the app has permission to use your display and graphics. Go to System Preferences > Security & Privacy > Privacy and look for any display or graphics-related permissions.

6. Reinstall the app:
- If none of the above works, uninstall Zen Color completely, then download and install the latest compatible version again.

If you’ve already tried some of these, let me know which ones, and we can dive deeper. Also, if there’s any error message or specific behavior, please share that—it’ll help me pinpoint the solution.

Are you able to try these steps?