Cosmos vs Rhythmic Blue
Both from Sherwin-Williams's palette. These are both blues, so the question isn't which hue to choose — it's where within blue to land. Rhythmic Blue (LRV 69) reflects noticeably more light than Cosmos (LRV 38), a difference of 31 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. With a ΔE of 20.7, 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 2 real-room photo comparisons where both colors appear side by side, plus 5 simulated room previews.
Cosmos vs Rhythmic Blue in Real Spaces
2 real rooms side by side. Seeing Cosmos and Rhythmic Blue in actual rooms makes the difference concrete; browse the spaces below to get a feel for how each color lives on a wall.
Bedroom
The context that matters most in a bedroom is how a color reads under a bedside lamp at night, not under noon daylight. Rhythmic Blue reflects noticeably more light off the walls, making the space read more open than Cosmos.
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. Rhythmic Blue reflects noticeably more light off the walls, making the space read more open than Cosmos.
Color Details
Cosmos vs Rhythmic Blue Simulated Comparison
5 simulated room previews — drag the slider on each to see Cosmos on one side and Rhythmic 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 Cosmos comparisons
See how Cosmos stacks up against other well-photographed colors across different brands and tones.
At LRV 83 vs 38, White Dove is decisively the brighter choice.
Purbeck Stone reflects far more light (LRV 52 vs 38), opening up a space where Cosmos encloses it.
Cosmos reads slightly lighter (LRV 38 vs 30), a gap that shows most in low-lit rooms.
Agreeable Gray reflects far more light (LRV 60 vs 38), opening up a space where Cosmos encloses it.
At LRV 58 vs 38, Accessible Beige is decisively the brighter choice.
A 11-point LRV gap (38 vs 27) makes Cosmos the marginally brighter of the two.
French Gray reads slightly lighter (LRV 43 vs 38), a gap that shows most in low-lit rooms.
At LRV 55 vs 38, Tranquil Dawn is decisively the brighter choice.
A 6-point LRV gap (44 vs 38) makes Hardwick White the marginally brighter of the two.
Pure White reflects far more light (LRV 84 vs 38), opening up a space where Cosmos encloses it.
At LRV 66 vs 38, Balboa Mist is decisively the brighter choice.
At LRV 74 vs 38, Shoji White is decisively the brighter choice.
At LRV 38 vs 12, Cosmos is decisively the brighter choice.
At LRV 68 vs 38, Skimming Stone is decisively the brighter choice.
At LRV 38 vs 12, Cosmos is decisively the brighter choice.
A 8-point LRV gap (45 vs 38) makes Saybrook Sage the marginally brighter of the two.
Cosmos reads slightly lighter (LRV 38 vs 31), a gap that shows most in low-lit rooms.
Cosmos reflects far more light (LRV 38 vs 7), opening up a space where Pine Needle encloses it.
Cosmos reflects far more light (LRV 38 vs 24), opening up a space where Cement grey encloses it.
Guilford Green reflects far more light (LRV 57 vs 38), opening up a space where Cosmos encloses it.