[Tig] Canon 4K monitor

David Corbitt dcorbitt77 at comcast.net
Sat Jan 25 14:34:49 GMT 2014

Viewing distance is determined by the resolving ability of the eye (visual acuity) and the density of pixels in the display. Visual Acuity is a measure of our ability to discriminate the finest detail: either by discriminating two parallel lines apart (Vernier acuity) or two tiny spots or stars apart (point discrimination). The human visual system is capable of acuity of 1 min of arc or 60 cycles/degree of visual angle. This is also the definition of 20/20 vision. The idea is to sit just far enough from the display so the individual picture element pixels are not detectable but not so far away that image detail of the finest size is still distinguishable from its neighboring detail dot. Too far away and the finest detail is combined with its neighbor by your retina, too close and the mechanical structure of display pixel elements become visible. I could quote all the mathematical formulae to determine ideal viewing distance but won’t at this time. Here’s a synopsis:
The rule of thumb that is commonly used for viewer distance calculations is

HD (1080)     3 picture heights

SD (625)       around 5 picture heights

SD (525)       around 6 picture heights           

Since 4K will have approximately 2 x the number of visible scan lines the viewing distance works out to be 1 1/2 picture heights.

When I was at HBO Studios designing and building screening rooms for QC, I did a lot of research on this topic and created an in house white paper to describe in detail all the parameters needed to satisfy the bio-physical needs of the human eye. The above info is taken from that paper.

Dave Corbitt

On Jan 24, 2014, at 7:28 PM, Robert Frye <bcfrye at earthlink.net> wrote:
> Bob - 
> Absolutely - what was the common figure?  2 - 3 screen height was the proper distance to view a monitor.  In Japan, during our early prototype reveals of the PRM, we discovered that the colorists there typically sit 1 to 1 & 1/2 screen heights away... due mostly to the smaller rooms they work in… but interestingly enough, that's now the preferred 4K viewing distance!
> We always recommended the surround walls to be 18% gray (grey??) for the best and most neutral color interpretation on screen.  Although you can imagine the variation in this that we found as we toured many different grading facilities around the world !!
> And yes, once the monitor dominates the field of view, the surround becomes more a part of the colorist's peripheral vision and less affecting of their color perception on screen.
> That doesn't mean we can have odd-ball colors in the surround walls of course :)   I'd bet even on the periphery, colors other than 18% gray will have some effect on the viewer.
> Not to mention the beverages of choice that some folks like to consume :)  … pass me the lime please !
> Bob
> On Jan 24, 2014, at 3:35 PM, Bob Friesenhahn wrote:
>> On Fri, 24 Jan 2014, laco wrote:
>>> I had the privilege to spend dinner with one of the Japanese engineers of this display after they presented it on a show in my country.
>>> He said that the optimal/recommended viewing distance is very close, I can’t recall the exact distance, but it was around 3 feet, maybe between 2-3 feet?
>> In the old days, the viewing distance was quite far compared to the size and resolution of the display. Quite a lot of attention was put into the color of the wall behind the display.  If one's face is only two feet away from the display, then it seems that the influence of the colors behind the display will be changed since the display occupies most of the field of view.
>> Bob

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