For clarity, when I said:
for a single sensor, I meant a monochrome sensor.
I think everyone has a slightly different take, as illustrated by the paper above.
Here is my half baked thought process, which may explain the may in the white-red-blue triple exposure thinking, and which will likely change as experience comes along.
The film contains information, including defects. I quoted this mission statement before taken from @friolator
to digitally reproduce the film as closely as we can, not so much the picture the film contains
Indeed.
It is clear we may not be able to capture all, and the conundrum of light and sensor is a fundamental decision on what is captured, and what is not.
Moreover, stacking provides a great workaround to extend the dynamic range on the sensor.
I think the goal of a scanner is not a ready to play version of the film. If we treat the film as information, the goal is to extract as much information as able within the limitations of time, quality, and cost. And cost/time is a critical factor for many who have a lot of film.
If we treat the film as signal and noise, the digital representation of a frame should have the best resolution (that one’s money can afford) and the signal to noise the dynamic range that the capture/channel can provide.
If the image in the film is signal, a tri-band narrow-band led is a filter, and I do not know yet what is lost in making that choice of discarding everything outside those 3 narrow bands. Something is lost, I do not know if it is relevant, but is lost.
Color sensors, also make a choice of what gets captured, and what is not, given by the sensor color sensitivity, even when using a white illuminant. But the band on the sensor color sensitivity is not narrow, so the limiting factor is the LED narrow band.
So if the film is information, the monochrome sensor is the wide band receiver, which requires a wide band antenna (the white illuminant). That’s great, but the problem is the separation of colors. The blue and red narrow band exposures would then provide the additional information needed to render a color frame.
It is the same as is done in video recording, the white = luminance, the red and blue provide the ability to create B-Y and R-Y.
Is the above illuminant setup better than R-G-B? Depends on the goal.
If the goal is to have a pleasing image, by definition of the narrow band RGB filters (leds), may be best.
If the goal is to capture the most information from the film, then a wide band capture (Y-White-Monochrome) will definitely keep more of it, and granted, more noise too. The narrow band blue and red LED is also not ideal, but it may be a cost effective trade-off.
In the White-Red-Blue exposures scenario is also worth mentioning that if there is no stacking, then the levels for the R and B illuminant should be adjusted for the best use of the dynamic range of the sensor/bit depth chosen for storage, which would provide better results when color correcting for finishing. And yes, why not consider separate channel stacking.
The same is also a consideration if using R-G-B LEDs and a color sensor with RAW files, go for the best use of the bit depth for each channel, not for the best color rendition.
The above is my thought process, and I am not aware of any scanner using this method.