I think that it boils down to two different choices:
- Color-reversal: you have broad dyes in your film stock, designed to give good colors when viewed in a projection setting. Projection-setting equals broad spectrum illumination, ideally similar to a Halogen lamp. Your digital camera should be tuned to “view” the colors as similar as a human observer does.
- Negative: this type of material used to be projected onto positive film material or paper. The sensitive dyes in the receivung medium are usually tuned more narrowly than the broadband “receivers” of a human eye. So it’s better here to use narrow-band illumination. Color science is weird here, as it depends on both the negative and positive material’s characteristic. You have to choose your sampling wavelengths carefully, otherwise you might end up with weird color shifts especially for colors located at spectral places you do not sample with your narrow-band LEDs.
Some people have tested whitelight illumination combined with narrow-band RGB-LEDs, some even implemented multi-spectral narrow-band setups. You might enjoy looking at their results.
While a narrow-band or even multi-spectral setup enables you to raise the separation of color channels, you generally end up with not having a good color science available. That is: there is a chance that the colors you get from your footage might be off. Compare the two results here- the color of the lamp post is especially different in both scans. The question is: which one is the correct one? Probably it boils down to personal taste ….