Name the Farrow & Ball shade you are looking at
Sample the color in even, indirect light and away from glare. The app returns the closest Farrow & Ball name and number, such as Hague Blue No.30 or Elephant's Breath No.229, with the HEX value it measured.
Because these colors are pigment-heavy, sample two or three spots on the same surface and keep the result that repeats. A single tap under a warm bulb can read a full step warmer than the paint really is.