Cook's Blue vs RAL 610-3
Cook's Blue (Farrow & Ball) and RAL 610-3 (RAL Effect) come from different manufacturers. Both sit in the blue family, which is useful context if you're narrowing within a single hue direction. Their light reflectance values are nearly the same — 25 vs 27 — so neither will read significantly brighter or darker than the other. A ΔE of 1.9 puts them in subtle territory — distinguishable in direct comparison, less so from across a room. Below you'll find 5 real-room photo comparisons where both colors appear side by side, plus 5 simulated room previews.
Cook's Blue vs RAL 610-3 in Real Spaces
5 real rooms side by side. Cook's Blue and RAL 610-3 are close enough that the difference can be hard to judge from a chip alone — these photos show how each reads at scale, across different spaces and lighting conditions.
Living Room
A living room wall sees more varied light than almost any other surface in the house, which makes the choice between these two more nuanced than a chip suggests. At this scale the difference is subtle — you'd need them side by side, as shown here, to reliably tell them apart.
Bedroom
Bedrooms are typically lit with warmer, lower light than the rest of the house — a condition that flatters warm tones and deepens cool ones. In photos like these you're seeing the difference at its most direct. In a finished room, the distinction is there but not dramatic.
Bathroom
Small bathrooms intensify color. A shade that seems quiet in a larger room can feel immersive when you're surrounded by it on four walls. In photos like these you're seeing the difference at its most direct. In a finished room, the distinction is there but not dramatic.
House
A full exterior is the most demanding test for a paint color — scale and outdoor light both amplify differences that seem small on a swatch. In photos like these you're seeing the difference at its most direct. In a finished room, the distinction is there but not dramatic.
Kitchen Cabinets
Cabinet color is always seen in context — against countertops, backsplash, and hardware — which amplifies undertone differences that might disappear on a plain wall. In photos like these you're seeing the difference at its most direct. In a finished room, the distinction is there but not dramatic.
Color Details
Cook's Blue vs RAL 610-3 Simulated Comparison
5 simulated room previews — drag the slider on each to see Cook's Blue on one side and RAL 610-3 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 Cook's Blue comparisons
See how Cook's Blue stacks up against other well-photographed colors across different brands and tones.
Ammonite reflects far more light (LRV 69 vs 25), opening up a space where Cook's Blue encloses it.
At LRV 83 vs 25, White Dove is decisively the brighter choice.
At LRV 25 vs 6, Cook's Blue is decisively the brighter choice.
Purbeck Stone reflects far more light (LRV 52 vs 25), opening up a space where Cook's Blue encloses it.
Evergreen Fog reads slightly lighter (LRV 30 vs 25), a gap that shows most in low-lit rooms.
At LRV 52 vs 25, Mizzle is decisively the brighter choice.
Agreeable Gray reflects far more light (LRV 60 vs 25), opening up a space where Cook's Blue encloses it.
At LRV 58 vs 25, Accessible Beige is decisively the brighter choice.
Their light reflectance is nearly identical (LRV 27 vs 25), so neither reads brighter in a room.
French Gray reflects far more light (LRV 43 vs 25), opening up a space where Cook's Blue encloses it.
Cook's Blue reflects far more light (LRV 25 vs 4), opening up a space where Naval encloses it.
At LRV 55 vs 25, Tranquil Dawn is decisively the brighter choice.
A 12-point LRV gap (25 vs 13) makes Cook's Blue the marginally brighter of the two.
At LRV 44 vs 25, Hardwick White is decisively the brighter choice.
Pure White reflects far more light (LRV 84 vs 25), opening up a space where Cook's Blue encloses it.
Cook's Blue reads slightly lighter (LRV 25 vs 21), a gap that shows most in low-lit rooms.
At LRV 66 vs 25, Balboa Mist is decisively the brighter choice.
At LRV 74 vs 25, Shoji White is decisively the brighter choice.
At LRV 83 vs 25, Snowbound is decisively the brighter choice.
Pigeon reflects far more light (LRV 51 vs 25), opening up a space where Cook's Blue encloses it.
At LRV 25 vs 12, Cook's Blue is decisively the brighter choice.
At LRV 25 vs 8, Cook's Blue is decisively the brighter choice.
At LRV 68 vs 25, Skimming Stone is decisively the brighter choice.
Dix Blue reflects far more light (LRV 41 vs 25), opening up a space where Cook's Blue encloses it.
At LRV 25 vs 12, Cook's Blue is decisively the brighter choice.
At LRV 45 vs 25, Saybrook Sage is decisively the brighter choice.
Pale Green reads slightly lighter (LRV 31 vs 25), a gap that shows most in low-lit rooms.