Signal blue vs RAL 640-M
Signal blue (RAL Classic) and RAL 640-M (RAL Effect) come from different manufacturers. These are both blues, so the question isn't which hue to choose — it's where within blue to land. The 5-point LRV gap — 10 for Signal blue vs 5 for RAL 640-M — means Signal blue will open up a space more effectively. ΔE 4.5 means they're clearly different, but not dramatically so — they'd pair well in the same room. Below you'll find 1 real-room photo comparison where both colors appear side by side, plus 5 simulated room previews.
Signal blue vs RAL 640-M in Real Spaces
1 real room side by side. Signal blue and RAL 640-M are close enough that the difference can be hard to judge from a chip alone — these photos show how each reads at scale, across different spaces and lighting conditions.
House
A full exterior is the most demanding test for a paint color — scale and outdoor light both amplify differences that seem small on a swatch. Signal blue has the edge in reflectance, which shows as a quiet sense of added space rather than an obvious contrast.
Color Details
Signal blue vs RAL 640-M Simulated Comparison
5 simulated room previews — drag the slider on each to see Signal blue on one side and RAL 640-M 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 Signal blue comparisons
See how Signal blue stacks up against other well-photographed colors across different brands and tones.
