Why do the red neon lights I shot with my Nikon D90 turn out to be more orange?

This is related to "color rendering", which is "the degree to which the light source presents the color of the object."

For example, all colors under sunlight can be displayed accurately. This is because sunlight is composed of light of various colors. A more physical explanation is that sunlight contains continuous The spectral components range from short-wave purple light to long-wave red light, with blue, cyan, green, yellow, and orange in between (visible light bands only). In this way, thousands of colorful objects in the world can reflect the corresponding color light in the sun and restore their inherent colors. This is not the case with artificial light sources. Common warm-tone incandescent lamps. But as long as the white balance is calibrated (film photography uses light negatives or installs a color temperature mirror), all colors can still be accurately restored. This is because the light emitted by incandescent lamps still contains continuous spectral components, but the content of long-wave yellow and red light is larger. The white balance setting allows excess warm light to be color compensated from the camera. In contrast, with other artificial light sources, even if you use the most accurate custom white balance, some colors still cannot be accurately restored. Its spectral components are not continuous and are missing in some bands.

Specific data, the color rendering of light sources that can emit a continuous spectrum is 100, fluorescent lamps are only 70, high-pressure neon lamps can be close to 60, and street lamps and square lighting have color renderings of less than 40. Red neon lights (ordinary neon lights) only emit red light and have very good monochromaticity. They are known as the best in monochromaticity. The wavelength distribution range is only 0.00001 nanometers. This is why you can’t capture true colors no matter how you correct the white balance in this type of situation.

To put it simply, red neon light is not a continuous spectrum, so it is impossible to perfectly reproduce it in photos.

The color temperature settings of the D90 are quite detailed. Appropriate settings can make the shots more realistic. You can read the manual, page 117: /view/95d23e40336c1eb91a375da1.html.

In fact, the human eye is very complex. No matter how good the camera is, it cannot perfectly interpret the feelings of the human eye. It is almost enough.