The low light scene is shot with Auto White Balance, to show how the camera's JPEGs look under artificial light. Any 'keep warm tone' options are left at their default setting.
The low light scene Raws are processed to demonstrate the capability of cameras in low-light shooting situations. Noise reduction is minimized and the white balance is neutralized to reveal blue channel noise. The black level is lifted to prevent noise being hidden by clipping. A standardized amount of sharpening is applied in Photoshop.
The X-T1's Auto White Balance gives a very neutral result with the low colour temperature tungsten lights used in this test, bringing just a slight hint of warmth to the image. This contrasts with the Olympus OM-D E-M1, which by default gives a strong orange cast here (although it can be set to be completely neutral, if you prefer). Other brands tend to lie somewhere between these two extremes, although Samsung tends towards complete neutrality.
The major difference in low light compared to daylight is that noise kicks in a bit sooner (here's an example taken at ISO 1600), though it's still relatively minor. Even in the shadows at ISO 6400, the text on the tubes of paint are still legible. Fine detail goes south at ISO 12800 and especially at ISO 25600, and while ISO 51200 just about retains some detail in the highlights, there's barely anything in the shadows except noise.
The results in Raw mode are essentially the same as they were in good light. Again it's crucial to bear in mind that the X-T1's X-Trans CMOS sensor requires different processing to the other comparison cameras, which essentially applies non-optional noise reduction resulting in much cleaner-looking images. The X-T1's optimistic ISO ratings also help make it look much better than its peers here. But even taking this into account, high ISO image quality is very respectable, with barely any chroma noise even in the shadows.