Impromptu vs Thames Fog
Impromptu is a Sherwin-Williams color while Thames Fog comes from Valspar. Impromptu reads as blue, while Thames Fog reads as grey — two distinct hue families, not close cousins. At LRV 27 vs 23, Thames Fog will read as the brighter of the two — a 5-point gap that matters most in north-facing or low-light rooms. At ΔE 39.7, these are genuinely distinct colors — a strong contrast if used together, or a meaningful choice between two different directions. Below, 5 simulated room previews show how each color reads at scale — real-room photos will be added as they become available.
Color Details
Impromptu vs Thames Fog Simulated Comparison
5 simulated room previews — drag the slider on each to see Impromptu on one side and Thames Fog 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 Impromptu comparisons
See how Impromptu stacks up against other well-photographed colors across different brands and tones.
