4K resolution
So while 4K UHD sounds like it has a pixel structures with 1/4 the area of 1080p, that does not happen with pixel shifting. Only a true 4K projector offers that level of resolution. That's why "true" 4K projectors cost so much more than 4K UHD projectors with otherwise similar feature sets. They produce smaller pixels, finer resolution, no compromising of detail or color from overlapping pixels. By comparison, the slight difference in aspect ratio between DCI and 3840×2160 pixel displays without overlap is insignificant relative to the amount of detail.
Da Vinci Systems
The da Vinci 2K Color Corrector, manufactured starting in 1998, was a completely revised color correction system that supported HDTV, SDTV, and 2K formats. The later system, the 2K Plus with improved color corrector tools was used on high-end DataCines and telecines like Thomson-Grass Valley's Spirit Datacine and Cintel's C-Reality & ITK Millennium. The 2K operated with a 4:2:2, 4:4:4 or 8:4:4 input in NTSC or Pal. In HDTV it operated with either 4:2:2 or 4:4:4 inputs. Many were interfaced to the Spirit DataCine.