How this match is calculated
Every Kilz and Farrow & Ball color in our database is converted to CIELAB coordinates, then scored with the CIEDE2000 formula — the current ISO standard for how different two colors look to the human eye. It corrects for the fact that the eye notices small shifts in some hue ranges far more than others, so it predicts real-world appearance more reliably than comparing hex codes directly.
Light Blue ranks as the closest Farrow & Ball equivalent to Patio Gray because it sits nearest in that perceptual space. The two are very similar — the difference shows side by side but is rarely noticeable across a room. Sheen, lighting, and the existing wall color all shift perceived color, so order a sample of Light Blue and check it in your actual room before committing.