Stone Blue vs RAL 660-3
Where Stone Blue belongs to Farrow & Ball's range, RAL 660-3 is a RAL Effect color. Both sit in the blue family, which is useful context if you're narrowing within a single hue direction. They have nearly identical light reflectance values (28 vs 27), so they'll read as similarly Medium in most lighting conditions. With a ΔE of 15.1, the contrast is hard to miss. These aren't variations on a theme — they're two different answers to the same question. Below you'll find 6 real-room photo comparisons where both colors appear side by side, plus 5 simulated room previews.
Stone Blue vs RAL 660-3 in Real Spaces
6 real rooms side by side. Seeing Stone Blue and RAL 660-3 in actual rooms makes the difference concrete; browse the spaces below to get a feel for how each color lives on a wall.
Living Room
In a living room, color works across both daylight and evening light — the same wall can read very differently at noon and at 8pm. Side by side like this, the difference is easy to read — which is exactly why seeing them in a real space is more useful than comparing chips.
Bedroom
The context that matters most in a bedroom is how a color reads under a bedside lamp at night, not under noon daylight. The distinction reads clearly at room scale, making the choice between them concrete.
Kitchen
In a kitchen, colors are seen under bright task lighting that amplifies undertones — what reads neutral elsewhere can show its hand here. The distinction reads clearly at room scale, making the choice between them concrete.
Bathroom
Bathrooms are one of the few spaces where you're genuinely enclosed by the paint color, which makes the choice between these two more consequential. The distinction reads clearly at room scale, making the choice between them concrete.
House
Seen across an entire facade, subtle tonal differences become pronounced. What reads as nearly the same on a chip often reads as clearly different at scale. The distinction reads clearly at room scale, making the choice between them concrete.
Kitchen Cabinets
Kitchen cabinets are constantly compared against adjacent materials, which means subtle differences between these two become much more visible. The distinction reads clearly at room scale, making the choice between them concrete.
Color Details
Stone Blue vs RAL 660-3 Simulated Comparison
5 simulated room previews — drag the slider on each to see Stone Blue on one side and RAL 660-3 on the other.
Digital color is approximate. These simulations are generated from the manufacturer's hex values and overlaid on grayscale room photos — your screen's calibration, brightness, and viewing angle all affect how they render. Before committing to either color, test physical samples in your own space under the light you actually live with.
More Stone Blue comparisons
See how Stone Blue stacks up against other well-photographed colors across different brands and tones.
