I was working on a RAW file in Photoshop CC and did some minor adjustments using Curves and Gradient Map layers.

I saved a file in PNG format to my desktop and noticed that the colours were unlike those I was seeing while in Photoshop.

I then saved another copy as PNG but this time using the 'Save For Web' option and the photo looked like what I had been seeing in Photoshop.

Does anyone know why this difference is being caused?