Honest color

An image carries a colour profile saying what its numbers mean; a display has one saying what it can show. Most viewers ignore both and send the numbers straight to the screen, which is why the same photo looks oversaturated in one program and right in another.

nitid reads the profile out of the file, asks Windows what the display is, and converts between them in the shader — the decoded pixels stay as the file stored them, the conversion costs nothing per frame, and changing your display profile costs a redraw rather than a reload.

• A wide-gamut file (Display P3, Adobe RGB) is brought into what the display can actually show, rather than clipped.
• A file with no profile is shown exactly as it is, the way Windows, the shell preview and every browser show it. It looks the same here as it does everywhere else — including in whatever tool made it. Guessing sRGB and converting from it would visibly wash the picture out on a wide-gamut display; see ADR 0005.
• Arbitrary tone curves are handled by sampling them, so a scanner or camera profile costs the same as a simple gamma.

When the image and the display already agree, no conversion happens at all and the hardware does the sRGB decoding for free.