Light & Optics Labλ = c / f • E = hf
680 nm to RGB & Color Calculator
Approximate how 680 nm monochromatic spectral light can be represented in sRGB, and calculate CIE 1931 tristimulus values, THz frequency, and photon energy.
CIE 1931 Spectral Synthesis
Red680 nm
#FF1F00
nm
380 nm (Violet)555 nm (Peak)750 nm (Deep Red)
Frequency
440.871 THz
Photon Energy
1.823 eV
sRGB Channels
255, 31, 0
CIE 1931 XYZ
0.0372, 0.0189
Why You See This Color (680 nm)
At 680 nm, Long-wavelength sensitive (L) cone responses dominate, although cone sensitivity curves overlap rather than switching on or off at exact boundaries. With a frequency of 440.871 THz and lower photon energy (1.823 eV), this stimulus is generally perceived as deep red. Near the 700–750 nm boundary, eye sensitivity tapers toward the infrared threshold.
Physical Parameter Breakdown
Wavelength (λ):680 nm (680 × 10⁻⁹ m)
Oscillation Frequency (f):440.871 THz
Photon Quantum Energy (E):1.823 eV
CIE 1931 Tristimulus (XYZ):X:0.0372 Y:0.0189 Z:0
Traian AnghelAuthor & Reviewer
Physics Teacher & Educational Technologist • Brăila, Romania
Last Reviewed: August 2026
Wave Lab calculators are constructed using rigorous peer-reviewed physics formulas from verified metrological repositories. Every equation, spectral conversion, and acoustic property is tested against NIST, CIE, and ISO datasets.
Verified Sources:NIST CODATACIE 1931 2° ObserverNASA Glenn Research
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