Color Contrast Problem....Need to reset to default for MacBook Air.

To fix a sudden color contrast or distortion problem on your MacBook Air, you usually do not need to completely erase or factory reset the computer. In almost all cases, this issue is caused by an accidentally triggered accessibility feature or an altered display setting. 

Try this

1. Click the Apple Menu  in the top-left corner of your screen and select System Settings (or System Preferences on older macOS versions).
2. Click Accessibility in the left sidebar, then select Display.
3. Locate the Display Contrast slider and slide it all the way to the left (Normal).
4. Make sure Increase contrast and Invert colors are toggled Off.
5. Scroll down to Color Filters and ensure it is toggled Off. 

and this

Go to System Settings → Displays.

Look for the Color Profile drop-down menu.

Select the default factory profile, which is usually named Color LCD (or the native profile designated for your specific MacBook Air display