DxOMark image quality testing protocols for lenses and sensors
Testing protocol for color sensitivity
Color sensitivity measurement requires knowing the RAW response of the sensor to a selection of known colors.
For this purpose, we shoot an image of a color target with perfectly-known reflectance spectra using a controlled and spectrally-measured illuminant.
We perform all color measurements using a dedicated Kyoritsu color light box, which provides uniform lighting over a surface about 50cm wide. The device enables to switch between several normalized illuminants (e.g., A, D65, CW, etc.).
The target is a Gretag Macbeth ColorChecker composed of 18 uniform color patches and 6 gray level patches. For each illuminant, we measure the reflection spectra of the patches with a spectrometer, and then we measure the RAW image values.
The uniformity of the illuminance is below 7% (checked with a lux-meter).
Read more about color measurement.