Banding/gradient issues

@SarahJorg  This could be an ICC Display profile thing.

A Display ICC profile contains a calibration and a characterisation of the calibrated display. That calibration is generally loaded into the device video card. The application uses the characterisation part of the [profile to adjust the data to correct screen appearance. 

Did you make an ICC display profile using an external calibration sensor like the Calibrite i1 Display range? 

Some display manufacturers default display ICC profiles are flawed, some ICC profiles apply quite extreme corrections in the calibration - especially if the calibration/profiling target values are a long way from the display's native characteristics. 

This is a strong marketing reason Hardware Calibration displays such as Eizo Coloredge were invented. The hardware calibration is FAR less likely to cause posterisation in images. However, not everyone can afford them and not everyone really needs them.

I suggest you have a look in Settings/Displays and see "Color Profile" 

You could try selecting the sRGB ICC profile there (it's not going to be accurate but it might change the 'banding' characteristics.)

If I was doing this I'd look up the claimed display colourspace, if it's sRGB use that, if it's Adobe RGB, use AdobeRGB1998.icc. 

This is strictly a temporary measure. Ideally you'd make an ICC display profile using an external calibration sensor like the Calibrite i1 Display range.

You could also do an "all reset" to get the display back to "as shipped".  That might help in one step.

I hope this helps

neil barstow, colourmanagement net - adobe forum volunteer - co-author: 'getting colour right'
google me "neil barstow colourmanagement" for lots of free articles on colour management

what app?