Reading Spectral emissions from modern light sources (more graphs added) reminded me of
The RAW to ACES Utility or
rawtoaces, is a software package that converts digital camera RAW files to ACES container files containing image data encoded according to the Academy Color Encoding Specification (ACES) as specified in SMPTE 2065-1. This is accomplished through one of two methods.
- CameraRAW RGB data (generated by libraw) is converted to ACES by calculating an Input Device Transform (IDT) based on the camera’s sensitivity and a light source.
- CameraRAW RGB data (generated by libraw) is converted to ACES by calculating an RGB to XYZ matrix using information included in
librawand metadata found in the RAW file.
The output image complies with the ACES Container specification (SMPTE S2065-4).
rawtoacesuses one of three methods to convert RAW image files to ACES.
- Camera spectral sensitivities and illuminant spectral power distributions
- Camera file metadata
- Camera data included in the
The preferred, and most accurate, method of converting RAW image files to ACES is to use camera spectral sensitivities and illuminant spectral power distributions, if available. If spectral sensitivity data is available for the camera,
rawtoacesuses the method described in Academy document P-2013-001 (.pdf download).
While preferred, camera spectral sensitivity data is not commonly known to general users. When that is the case,
rawtoacescan use either the metadata embedded in the camera file or camera data included in
librawto approximate a conversion to ACES.
Examples of such data could be found here: https://github.com/ampas/rawtoaces/tree/master/data/camera.