Sea Urchin 3 vs Blithe Blue
Where Sea Urchin 3 belongs to Dulux's range, Blithe Blue is a Sherwin-Williams color. These are both blues, so the question isn't which hue to choose — it's where within blue to land. Blithe Blue (LRV 46) reflects noticeably more light than Sea Urchin 3 (LRV 40), a difference of 6 points that becomes especially apparent in rooms with limited natural light. Both lean cool, so they'll behave similarly in mixed or changing light conditions. The ΔE 6.4 gap is real but not dramatic — close enough to use together, distinct enough to matter as a choice. Below you'll find 1 real-room photo comparison where both colors appear side by side, plus 5 simulated room previews.
Sea Urchin 3 vs Blithe Blue in Real Spaces
1 real room side by side. Sea Urchin 3 and Blithe Blue 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.
Bedroom
The context that matters most in a bedroom is how a color reads under a bedside lamp at night, not under noon daylight. Blithe Blue reads slightly lighter here — a subtle but real difference in how open the space feels.
Color Details
Sea Urchin 3 vs Blithe Blue Simulated Comparison
5 simulated room previews — drag the slider on each to see Sea Urchin 3 on one side and Blithe Blue 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 Sea Urchin 3 comparisons
See how Sea Urchin 3 stacks up against other well-photographed colors across different brands and tones.
At LRV 69 vs 40, Ammonite is decisively the brighter choice.
White Dove reflects far more light (LRV 83 vs 40), opening up a space where Sea Urchin 3 encloses it.
Sea Urchin 3 reflects far more light (LRV 40 vs 6), opening up a space where Iron Ore encloses it.
A 12-point LRV gap (52 vs 40) makes Purbeck Stone the marginally brighter of the two.
A 10-point LRV gap (40 vs 30) makes Sea Urchin 3 the marginally brighter of the two.
Mizzle reads slightly lighter (LRV 52 vs 40), a gap that shows most in low-lit rooms.
At LRV 60 vs 40, Agreeable Gray is decisively the brighter choice.
Accessible Beige reflects far more light (LRV 58 vs 40), opening up a space where Sea Urchin 3 encloses it.
Sea Urchin 3 reflects far more light (LRV 40 vs 27), opening up a space where Denim Drift encloses it.
A 3-point LRV gap (43 vs 40) makes French Gray the marginally brighter of the two.
At LRV 40 vs 4, Sea Urchin 3 is decisively the brighter choice.
Tranquil Dawn reflects far more light (LRV 55 vs 40), opening up a space where Sea Urchin 3 encloses it.
Sea Urchin 3 reflects far more light (LRV 40 vs 13), opening up a space where Bancha encloses it.
Hardwick White reads slightly lighter (LRV 44 vs 40), a gap that shows most in low-lit rooms.
At LRV 84 vs 40, Pure White is decisively the brighter choice.
At LRV 40 vs 21, Sea Urchin 3 is decisively the brighter choice.
Balboa Mist reflects far more light (LRV 66 vs 40), opening up a space where Sea Urchin 3 encloses it.
Shoji White reflects far more light (LRV 74 vs 40), opening up a space where Sea Urchin 3 encloses it.
Snowbound reflects far more light (LRV 83 vs 40), opening up a space where Sea Urchin 3 encloses it.
A 11-point LRV gap (51 vs 40) makes Pigeon the marginally brighter of the two.
Sea Urchin 3 reflects far more light (LRV 40 vs 12), opening up a space where Pewter Green encloses it.
Sea Urchin 3 reflects far more light (LRV 40 vs 8), opening up a space where Duck Green encloses it.
Skimming Stone reflects far more light (LRV 68 vs 40), opening up a space where Sea Urchin 3 encloses it.
Their light reflectance is nearly identical (LRV 41 vs 40), so neither reads brighter in a room.
Sea Urchin 3 reflects far more light (LRV 40 vs 12), opening up a space where Vintage Vogue encloses it.
Saybrook Sage reads slightly lighter (LRV 45 vs 40), a gap that shows most in low-lit rooms.
A 9-point LRV gap (40 vs 31) makes Sea Urchin 3 the marginally brighter of the two.