Royal Regatta 6 vs Undercool
Where Royal Regatta 6 belongs to Dulux's range, Undercool is a Sherwin-Williams 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 (50 vs 49), so they'll read as similarly Medium in most lighting conditions. Both lean cool, so they'll behave similarly in mixed or changing light conditions. The ΔE 9.5 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
Royal Regatta 6 vs Undercool Simulated Comparison
5 simulated room previews — drag the slider on each to see Royal Regatta 6 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 Royal Regatta 6 comparisons
See how Royal Regatta 6 stacks up against other well-photographed colors across different brands and tones.
