Since the base data files are all in 4k, you would have a 400% increase in resolution, in addition to higher color density.
4k (UHD) is a totally different world.
Mr Harris, your noting that higher color density is another benefit of quadrupling Blu-ray's 1080p resolution with UHD displays and UHD source material, has me wondering how visually significant the improvement in color density could actually turn out to be. Already with 1080p Blu-ray my guests marvel at the richness of the reds and blues that appear on British uniforms and hats in early scenes of Lawrence of Arabia. And with my recently calibrated display, a short time ago I paused a scene of a salad bar where every fruit and vegetable looked exactly as it does in reality. The broccoli, for example,
from the deep, dark green of its flower, to its light green stalk, which then transitions into white, looked precisely as it does when it's on our dinner table.
During a movie, the other day, when a bag of Lay's potato chips appeared in a scene, I froze the action so that I could retrieve a bag of those potato chips from our cupboard. Sure enough, the famous yellow, red, and white colors of the bag on screen, were so close to the bag in my hand that I'd have to strain to even imagine that there was any significant difference in appearance between the two.
My basic question, Mr Harris, is that since high quality 1080p displays and material already have the capability to accurately reproduce the look of things such as apples, oranges, pears, cantaloupe, and bananas, how much difference can an increase in color density actually provide toward making such images seem even more realistic?