I bought an XPS15 9570, ultra HD, AdobeRGB display and was very disappointed with the unrealistic, gaudy colours. Searching for a solution online I found a lot of complex technical advice, mainly from photographers.
The solution I found was to search for Intel Graphics Control Panel, then go to:
display then color settings then change "color gamut" from the apparently default "vivid" to "natural"
tick to apply, and confirm
The display is now great - I hope this is helpful to those in the same situation. I think Dell should show this option during initial set-up