Cook's Blue vs RAL 580-4
Cook's Blue is a Farrow & Ball color while RAL 580-4 comes from RAL Effect. Both sit in the blue family, which is useful context if you're narrowing within a single hue direction. At LRV 25 vs 18, Cook's Blue will read as the brighter of the two — a 7-point gap that matters most in north-facing or low-light rooms. At ΔE 12.7, these are genuinely distinct colors — a strong contrast if used together, or a meaningful choice between two different directions. Below you'll find 4 real-room photo comparisons where both colors appear side by side, plus 5 simulated room previews.
Cook's Blue vs RAL 580-4 in Real Spaces
4 real rooms side by side. Seeing Cook's Blue and RAL 580-4 in actual rooms makes the difference concrete; browse the spaces below to get a feel for how each color lives on a wall.
Living Room
Living rooms test a color across a full range of conditions — morning sun, afternoon shade, and evening lamp light all shift how both of these read. Cook's Blue has the edge in reflectance, which shows as a quiet sense of added space rather than an obvious contrast.
Bedroom
Bedroom walls are often seen under warm artificial light, a context that shifts both colors from how they look on a chip. The brightness difference is modest but present — Cook's Blue gives the walls a little more lift.
Bathroom
Bathrooms amplify color — the enclosed space and reflective surfaces make what reads subtle elsewhere feel more present here. The brightness difference is modest but present — Cook's Blue gives the walls a little more lift.
Kitchen Cabinets
On cabinetry, undertone and temperature become more pronounced against countertops and hardware. The brightness difference is modest but present — Cook's Blue gives the walls a little more lift.
Color Details
Cook's Blue vs RAL 580-4 Simulated Comparison
5 simulated room previews — drag the slider on each to see Cook's Blue on one side and RAL 580-4 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 Cook's Blue comparisons
See how Cook's Blue stacks up against other well-photographed colors across different brands and tones.
