In this episode I chat to Andrew Stockman and Andy Rider.
Andrew is the Steers Professor of Investigative Eye Research and Andy is a Senior Research Fellow in the same Institute of Ophthalmology at University College London.
They have been responsible for lots of the research into redefining the color matching functions for the standard human observer since the early 2000’s. The Luminous efficiency functions and then updating the LMS cone responses.
Their work has formed the basis for the new standards adopted by the CIE, and has a lot of crossovers with the film industry and they regularly attend events discussing narrow band displays and observer metamerism failures. We chatted at length about the implications of their work.
I also had the pleasure of attending Andrew’s presentation at the AIC 2025 conference held in Taipei.
Andrew’s UCL website, where you can find the new CMF's: http://www.cvrl.org/
We discuss:
- (00:00) - Start.
- (00:47) - Introduction.
- (01:55) - Interview starts.
- (03:02) - Updating the standard human observer.
- (06:15) - Early cone research and standards.
- (08:52) - Measuring photopigments.
- (11:01) - Method of cone sensitivity measurement.
- (14:30) - Color matching functions and conversions.
- (15:11) - Narrow band primaries show errors in 1931CIE XYZ
- (17:43) - Context and cognition.
- (20:28) - Calibration and Individual differences.
- (22:47) - Trichromacy and opponency.
- (24:08) - Calculated luminance vs perceived brightness.
- (27:50) - Vision as spatial information extraction.
- (29:10) - Cone responses as a vital part of the cognition puzzle.
- (30:40) - Negative values caused by matrix transforms.
- (32:36) - Apple proposing color matching functions.
- (36:36) - Multi primary displays.
- (39:23) - LED Max multi band primary source.
- (40:57) - Ratios of cone types and links to evolution and other species.
- (42:15) - Eye vs camera differences.
- (43:48) - Chasing wider gamut’s and metamerism failure.
- (50:49) - Color matching functions the drive for rec 2020.
- (53:23) - Variable primaries.
- (55:41) - Comparing narrow and wide gamut, SDR and HDR.
- (57:09) - LED Max and Maxwell’s method.
- (01:00:01) - Fitting a models’ parameters to the measured data.
- (01:01:40) - Maxwell’s method vs maximum saturation matching method.
- (01:06:33) - Adding negative primaries while matching.
- (01:07:54) - Soundness of Grassman’s additivity.
- (01:09:53) - Proclivity for seeing patterns and geometric shapes.
- (01:12:29) - Future research topics.
- (01:13:57) - Genetic variations over time.
- (01:16:39) - Many solutions to spatial perception.
- (01:18:01) - Trichromacy through the ages.
- (01:21:52) - End of the interview.
- (01:22:12) - Andrew’s presentation at AIC 2025.
- (01:42:08) - Outro.
- (01:42:35) - End.
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