We asked our renderer to paint a wall in hex #3D5A47 (a deep sage green). The rendered wall averaged #3E5742, a Euclidean colour distance of 1.3% of the full RGB range. That is close enough that the difference disappears under normal room lighting variation.
The test
- Input: a real living-room photo, with an area mask over one wall.
- Instruction: paint only the masked wall in deep sage green, exactly hex #3D5A47, as flat matte interior paint.
- Measurement: average pixel colour sampled across the rendered wall region, compared to the target hex.
The result held even though the model renders realistic lighting on top of the paint colour: shadow and highlight variation averaged out to within 1.3% of the requested tone.
Why "colour comes out wrong" is a real complaint
Users of AI room apps report colours drifting badly. "It always comes up red," reads one review we studied. Two causes dominate:
- RGB sliders are the wrong interface. A person choosing paint thinks in named tones, not coordinates. A slider position also says nothing about how the model will interpret it.
- Colour instructions get lost in long prompts unless the pipeline treats them as hard requirements.
RoomMakeover sends both the colour name and the exact hex, marked as a precision requirement. That combination is what produced the 1.3% result. The palette offers 24 named tones across whites, neutrals, greens, blues, warm tones and deep shades.
Renders as a paint preview
If a render can hit a specified colour within ~1%, you can treat renders as a paint preview: render your wall in two candidate tones, view them on the actual photo of your room with your actual light, and buy one sample pot instead of four. The render will not replace a physical patch test (screen calibration and paint finish still matter), but it eliminates the worst mistake, which is choosing a colour family that fights the room.
One honest caveat
Our measurement is one room, one wall, one lighting condition. Colour accuracy can vary with very dark scenes or heavily filtered photos. Daylight photos with curtains open give the model the best base to build on.
