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.
Red Digital Cinema
The early team members engaged in undisclosed research on how to make a digital camera feasible for Hollywood productions. Part of this involved using 4K resolution instead of 2K which was most common at the time. Another technical hurdle was to achieve the focusing quality of DSLR cameras without sacrificing frame rate. Part of Red's solution to this problem was developing a sensor with a physical size comparable to that of analog film. At the 2006 NAB Show, Jannard announced that Red would build a 4K digital cinema camera, called the Red One, and began taking pre-orders.