Sky Fall vs Undercool

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. They have nearly identical light reflectance values (51 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 3.3 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.