ScanJet G4050 Review
The theory is that the usual source of white light used for scanning doesn't offer full-spectrum illumination, so a separate pass with a separate light source and some extra sensors can fill in the gaps and produce a more accurate result.
Pros: Good colour quality; reasonable build quality; decent support at the price for a wide range of different slide formats
Cons: Can be slow at higher resolutions; slight softening on both paper and slide scans; drivers and software need to be streamlined and simplified