RAL 670-4 vs Undercool
Where RAL 670-4 belongs to RAL Effect's range, Undercool 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. Undercool (LRV 49) reflects noticeably more light than RAL 670-4 (LRV 38), a difference of 11 points that becomes especially apparent in rooms with limited natural light. The ΔE 6.4 gap is real but not dramatic — close enough to use together, distinct enough to matter as a choice. Below, 5 simulated room previews show how each color reads at scale — real-room photos will be added as they become available.
Color Details
RAL 670-4 vs Undercool Simulated Comparison
5 simulated room previews — drag the slider on each to see RAL 670-4 on one side and Undercool 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 RAL 670-4 comparisons
See how RAL 670-4 stacks up against other well-photographed colors across different brands and tones.
White Dove reflects far more light (LRV 83 vs 38), opening up a space where RAL 670-4 encloses it.
At LRV 52 vs 38, Purbeck Stone is decisively the brighter choice.
A 7-point LRV gap (38 vs 30) makes RAL 670-4 the marginally brighter of the two.
At LRV 60 vs 38, Agreeable Gray is decisively the brighter choice.
Accessible Beige reflects far more light (LRV 58 vs 38), opening up a space where RAL 670-4 encloses it.
RAL 670-4 reads slightly lighter (LRV 38 vs 27), a gap that shows most in low-lit rooms.
A 5-point LRV gap (43 vs 38) makes French Gray the marginally brighter of the two.
Tranquil Dawn reflects far more light (LRV 55 vs 38), opening up a space where RAL 670-4 encloses it.
Hardwick White reads slightly lighter (LRV 44 vs 38), a gap that shows most in low-lit rooms.
At LRV 84 vs 38, Pure White is decisively the brighter choice.
Balboa Mist reflects far more light (LRV 66 vs 38), opening up a space where RAL 670-4 encloses it.
Shoji White reflects far more light (LRV 74 vs 38), opening up a space where RAL 670-4 encloses it.
RAL 670-4 reflects far more light (LRV 38 vs 12), opening up a space where Pewter Green encloses it.
RAL 670-4 reflects far more light (LRV 38 vs 8), opening up a space where Duck Green encloses it.
Skimming Stone reflects far more light (LRV 68 vs 38), opening up a space where RAL 670-4 encloses it.
RAL 670-4 reflects far more light (LRV 38 vs 12), opening up a space where Vintage Vogue encloses it.
Saybrook Sage reads slightly lighter (LRV 45 vs 38), a gap that shows most in low-lit rooms.
A 7-point LRV gap (38 vs 31) makes RAL 670-4 the marginally brighter of the two.