As we embrace 4K resolutions, we are already hearing of 8K and even 16K displays. While some may be content with 1080P, 4K is here to stay – until the next evolution in resolution. We have all seen articles like “Is 4K Really Necessary?” speaking to the availability of 4K sources and streaming bandwidth limitations… or that 4K has limited value unless viewed at close viewing distances. There is no doubt about sources and bandwidth, but the issue of visible differences begs for a discussion of visual acuity.
To a display, more pixels means smaller pixels, resulting in more detail on screen. While accurate, we need to relate to what the eye can resolve to explain the relevance of greater pixel count. The Snellen eye chart establishes that the smallest thing the eye resolves as an object 1 arc minute in size. The smallest we can see and recognize as something specific is 5 arc minutes.
There are 10,800 arc minutes in 180° of viewing, making this the maximum the eye can see. This means if we are far enough away that 1 pixel fills 1 arc minute, the eye has a “resolution” that would require an image no less than 10,800 pixels in both directions. To create this using 1080P projectors, we would need 5.6 projectors across, and 6.5 vertically, about 42 total (minimum). Clearly that is expensive and impractical, but provides an idea of what the eye can see. Now 4K, 8K, and 16K displays make more sense, because we can see a difference.
Resolution correlates directly to detail in the image, but it goes beyond pixel density. While a projection chip at 1080P does provide higher resolution than one at XGA, other variables such as the light engine, processor, optics, and the projection screen all have an impact on the ability to replicate the image accurately. The current standards for resolution being used relate to a combination of visual acuity and overall source detail on screen:
- 1920×1080: HD
- 2048×1080: 2K Digital Cinema
- 3840×2160: 4K UHDTV
- 4096×2160: 4K Digital Cinema
- 7680×4320: 8K UHDTV
- 15360×8640: 16K Digital Cinema
UHD is an example of where we are headed, beginning at 4K, going up to 8K… and includes advances in optics, processors, and sources that can leverage higher resolution and technology like HDR. There are few 8K sources available today, but an 8K display could also enhance lower resolution video other improved technologies. Resolutions such as 8K allow filmmakers to shoot in high resolution and edit to the appropriate size. NHK, Sony and Red Digital Cinema are currently embracing 8K, and filmmakers are pushing for more.
It is the combination of the projector, source, screen, and ambient light that makes the highest quality images possible. If the screen reflecting the image to the viewers is not compatible with higher resolutions, it becomes the weak link in the chain, reducing the overall viewing experience. It’s worth pointing out that all screen surfaces are not created equal.
Stewart Filmscreen is the technology leader in screen surfaces. For example, a Stewart 10’ wide screen is 3048mm… Stewart Filmscreen fabrics can resolve 6 arc minutes per millimeter. This means we get a product that can display 18,288 possible pixels per 10’ of screen width. This is greater than the resolution of a 16K projector (if one existed). Stewart fabrics can resolve resolutions well beyond the limit of the human eye.
Bottom line? As we progress from 8K to 16K and beyond, Stewart Filmscreen is ready and waiting.
This partner contribued content was written by Alan C. Brawn CTS, ISF, ISF-C, DSDE.