In the 90s, there was some pretty good hardware and software for color negative scanning. These days, what with the market size being minuscule, not no much. It strikes me that the CFA spectral response that's optimal for the real world is not optimal for teasing out the densities of the three dye layers of color negative film. I would think that using three exposures with different narrow-band illuminants tuned to the center wavelengths of the three dye layers would be better, although it would take a lot of experimentation to sort it all out. If you don't use a monochromatic sensor, you could equalize all of the CFA sites, rather than demosaicing.
Jim
The real world sensitivity of color negative films is not represented in the dye densities of the developed films. The last are aimed at the sensitivity of the chromogene color papers. Some months ago I converted a Philips PCS2000 color enlarger head to a slide/color - B&W negative copier with a 5D II camera + Sigma 50mm 2.8 macro lens attached. As the halogen lamps were gone and quite expensive to replace I bought some MR11 RGB LED lamps + a 3 channel LED dimmer. The spectral output fits the sensor quite well and the R and B hit the dye densities in an acceptable way but the Green LED at 525 NM peak should be wider, at least towards 540-550 NM, the Blues in the positive image shift too much as the yellow dye density is not hit well this way. Green LEDs are already less efficient than other LED colors but at 540NM the efficiency loss is the deepest in what is called "The Green Gap" in the LED industry. There are some developments (Lumileds for example) that should change that in time. Meanwhile I aim to bridge that spectral part with a white LED + a broader green camera filter. Another solution is a mix of an Amber and Green LEDs. Ideally the deviation between the peak film dye density at 540NM and the peak sensor sensitivity at 525NM should be compensated by a kind of fluorescence filter between film and sensor, all other narrow LED or (broad or narrow) green filters solutions are a compromise.
For B&W negatives I can replace the RGB LEDs with three 525NM Green LEDs. So far I only use one and the RB LEDs are not used in B&W copying. I wonder whether there would be a gain by using more of the Bayer sensor as discussed in this thread, the more that the lens should be optimal for green light and focusing on the sensor is done with green light only.
The Canon RAWs of the negatives are converted to positive "RAW" Tiffs in Vuescan and imported in ACR. That makes the ACR tools more usable than starting from negative RAWS. In practice the workflow of the color negative copies with more Vuescan involvement worked faster than a more "RAW" approach, image quality similar. For B&W the magenta images (Green LEDs) were only reversed in Vuescan. Grain (aliased without doubt) is sharp. I think that the B&W copies are at the level I could get with my Nikon 8000 scanner, but this goes faster. Wet mounting could be a next step for image quality, another camera too. Lens is good at this 1:1 magnification.
I still have to go the slide route, so far I modified the film holder of the Philips enlarger and that means film strips only. There exist boards for slides for that holder AFAIK but I envision a faster custom slide holder. Contemplated auto focus with the lens at fixed distance (filter thread support) and the camera moving (spring balanced for weight compensation) but for film strips the film plane deviation is not worth it, might change for a diversity of slide mounts though.
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htmMarch 2017 update, 750+ inkjet media white spectral plots