Adding red + green + blue light = white. Mixing cyan + magenta + yellow paint = black. Both are correct, in opposite physical systems. Light is emissive, sources add together. Paint is reflective, pigments absorb (subtract) wavelengths. Tunable white LED, RGB strip lighting, and stage colour-mixing all use additive. Inkjet, offset, paint, subtractive.
Four ideas to carry into the next specification conversation you have.
Red + green = yellow light. + blue = white. The eye perceives the combined wavelengths.
Each pigment absorbs (subtracts) certain wavelengths. Combined absorption = darker. All three = near-black.
Mix 2700K + 6500K LEDs. The two emissions add to create intermediate CCTs.
Pure additive RGB can't render certain pastel skin tones. Adding a white phosphor LED + RGB chips = wider gamut for stage and architectural lighting.
Where additive and subtractive each rule.
| Model | Primaries | Use |
|---|---|---|
| RGB additive | Red Green Blue | Light / displays |
| CMY subtractive | Cyan Magenta Yellow | Paint / pigment |
| CMYK printing | CMY + Key (black) | Inkjet / offset |
| RGB-W LED | RGB + White | Stage / architectural |
| Tunable white | Warm + Cool LED | Office / hospitality |
| RGBWA LED | + Amber | Skin tones / theatre |
| RGBL LED | + Lime | Saturation push |
Five places additive vs subtractive crosses in lighting design.
The eye sees painted surface = pigment subtractive × light source additive. Wrong light spectrum on right paint = wrong colour.
2700K LED + 6500K LED combined produces intermediate CCT. The mix is additive in the spectral domain.
Pure RGB has gamut limitations near white. RGBWA (with amber) or RGB + warm white needed for accurate skin in theatre and concerts.
Light wall (high reflectance) = bright room. Dark wall (low reflectance) absorbs subtractively. Same fixture, different room feel, interaction of additive light + subtractive paint.
Façade colour-changing uses RGB or RGB-W LED. Choice depends on whether designer wants saturated colour shows or accurate building-material rendering.
Our architectural RGB-W and RGBWA fixtures cover the full gamut including pastel skin tones. DMX-controlled for stage / façade / hospitality colour shows.
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