Spectrum Explorer
Connect wavelength, frequency and photon energy with a labelled display-color approximation. Choose the input quantity and units, use vacuum or an explicit propagation speed, and export the values with a schematic wave chart.
through the spectrum.
Enter a wavelength or frequency, then update the spectrum. Your values, approximate color and labelled wave appear here.
500 nm is ready as an example. Update spectrum to prepare your result.
Worked examples
How the display-color model works
The model uses RGB ramps over 380–440, 440–490, 490–510, 510–580, 580–645 and 645–780 nm. Edge attenuation rises from 0.3 at 380 nm to 1 at 420 nm, and falls from 1 at 700 nm to 0.3 at 780 nm. Each channel is rounded from 255 × (ramp × attenuation × brightness)⁰·⁸. The SVG and copied report preserve the model context.
Photon energy uses E = h × f with h = 6.62607015 × 10⁻³⁴ J·s. One eV is 1.602176634 × 10⁻¹⁹ J. Values are calculated with floating-point arithmetic; displayed summaries round to ten significant figures.
Accuracy. RGB is a display approximation, not a measured spectral color. Vacuum c=299792458m/s; no laser exposure, equipment safety or photometric claims.
Common questions
- What color is a wavelength of 500 nm?
- In this declared display model, a vacuum-equivalent wavelength of 500 nm at 100% display brightness gives RGB(0, 255, 146), or #00ff92. Its frequency in vacuum is 599584916000000 Hz and its photon energy is about 2.47968397 eV. An RGB display does not reproduce a measured monochromatic spectral color.
- How are wavelength, frequency and photon energy related?
- Frequency is propagation speed divided by wavelength: f = v / λ. Photon energy is E = h × f, using h = 6.62607015 × 10^-34 J·s. The eV conversion uses 1 eV = 1.602176634 × 10^-19 J. Vacuum speed is exactly 299792458 m/s; calculations use floating-point arithmetic.
- Does changing units change the physical value?
- No. Switching between wavelength units, frequency units, or the two input quantities converts the current valid value. For example, 500 nm is 0.5 µm or 0.0000005 m. Correct an invalid value before changing units; the tool keeps your input and explains the error.
- What happens when I enter a custom propagation speed?
- Applying a new speed holds the current frequency fixed and recalculates wavelength. The result labels that wavelength as in-medium. The color swatch uses the vacuum-equivalent wavelength c / f. For example, speed 149896229 m/s and wavelength 250 nm have the same frequency and approximate display color as 500 nm in vacuum.
- Which wavelengths have a color swatch?
- The model covers vacuum-equivalent wavelengths from 380 through 780 nm, including both endpoints. Outside that range the swatch is unavailable. The piecewise RGB ramps include attenuation at the visible edges and gamma 0.8. Display brightness scales only the approximate RGB swatch; it does not change frequency or photon energy.
- What is included in the SVG chart and copied values?
- Both include the input quantity, units, propagation speed assumption, wavelength, frequency, photon energy and color-model context. The SVG adds an original two-cycle schematic with a labelled wavelength. The wave amplitude is illustrative and has no physical unit; neither the chart nor the brightness control represents optical power.
- Are my values sent to a server?
- The conversion and SVG generation run in your browser. Valid settings are remembered on this device when browser storage is available. Restored values need an explicit Update spectrum action before a new result is prepared. Use the page's Start over control to forget the saved settings.
RGB is a display approximation, not a measured spectral color. Vacuum c=299792458m/s; no laser exposure, equipment safety or photometric claims.