Seeing more -  Is 8k enough?

Posted: 02.04.14

Visual resolution or acuity is the spatial resolving capacity of the visual system—the ability of the eye to see fine detail. It is further defined as target detection, which only requires the perception of the presence or absence of an aspect of the stimuli, not the discrimination of target detail. So it’s binary—you either see something (think of two back dots on a white background, next to each other separated by a white space of the same diameter) or you don’t. When you can’t detect there are two dots, you’ve reached the limit of your acuity or visual perception. It’s Shannon’s theory—any difference that makes a difference is how Gregory Bateson (famous cybernetician) translated Shannon’s works.

Sometimes the acuity is referred to as Just Noticeable Differences (JNDs)

There’s another (actually, there are many) measurement system called The Perceptual Quality Metric (PQM), which calculates expected viewer perceptions of quality based on display size, resolution, luminance, and color gamut.

Researchers at 3M made some measurements using PQM and produced the following chart.

AT THE RECOMMENDED VIEWING DISTANCE—1.5 times the display’s diagonal—the improvement from 1080p to 4K creates a strong increase in perceived quality.



At CES 2014 Sharp showed an 85- inch, 8K glasses-free 3D TV, and Samsung has a 98-inch 8K TV. That resolution, 7680 × 4320, is being called Quad Ultra HD, or QUHD for folks who like those crazy letter combinations. It is 33 megapixels, that’s even more than I have currently—I might be suffering from pixel envy.

Viewing distance is generally advised at 1.5x the display diagonal. However, I’m sitting in front of a 2500 × 1600 30- inch screen and am only 25 inches away; others in the office are at about the same ratio, the same distance away as the diagonal, so the 1.5x rule is mostly applied to TV watching, although we watch a 37-inch HDTV from about six feet away. Hmmm—in real life there is no rule.

STEP AWAY FROM THE SCREEN—how far away do the dots, lines, checkerboard merge?


Our empirical experience with the 4K displays is the same as with our other monitors, same as the diagonal. The 4K monitors are 32-inch.

But, what can you, do you, see? It’s tricky. If you take full advantage of the resolution and display your documents and spread-sheets at the normal magnification you use (I use 75%), then I find I have to lean in closer to the display to see stuff because it’s so small.

Now if you increase the magnification then you defeat, to some extent, the benefit of the added resolution, the stuff that will let you do more.
So like all things in life, there are trade-offs.

For me, 4K is great, but 8K is coming, and 8K is considered at the edge of, if not beyond, our acuity. What will an 8K computer monitor look like, assuming you can buy one small enough to fit on your desk? The short answer is great, they will look great. But, you’ll have to lean in to see stuff—and that makes a difference.

That may mean we’ve reached the point of practical limitation (diminishing returns) on computer displays for office work at 4K. However, for entertainment, like games, and photo/video work, 8K may be just what the doctor ordered. That being the case, you can then always revert back to increasing the magnification for office apps.

I am so looking forward to this.

For further reading

On 3M’s website, the company presents a study that is the first to document, in a scientific manner, the desirability of wide gamut. All display manufacturers and device manufacturers should read it. Another informative study is “Visual Acuity” by Michael Kalloniatis and Charles Luu.