Resolution is one of those terms that gets casually thrown around a lot these days. However, I’m willing to bet that if I polled twenty random folks on the street, I would receive twenty different (but still technically correct) definitions. This would be at no fault to my survey hostages participants. Misconceptions abound on the subject and half-truths seem to be the norm. The projector and TV industries aren’t doing us any favors, either; in recent history they’ve been running in a few different directions with regards to terminology and classifications. So, let’s whittle this vast subject down to it’s core factor: Pixels. By working from the smallest component up, we can peer through the murky waters of resolution. Let’s look at pixels in a little more (my apologies)…detail.
The term “Pixel” is a portmanteau of “Picture” and “Element.” They’re the building blocks of a digital image. Literally, they’re tiny squares of color. The more of these little guys you find in your display image, the better your resolution.
For brevity’s sake, we’ll focus on resolution ratios as they relate to televisions. However, the movie industry is inextricably burrowed into this discussion.
Right now, the highest resolution you can find in the consumer marketplace is 4K or “Ultra HD.” 4K refers to the amount of horizontal pixels in the display. In TVs, this is 3,840. Yes, astute reader, 3,840 is less than 4,000. Don’t freak out. You’re not being shorted 160. Don’t go into Best Buy demanding your missing pixels unless you need a free ride to jail.
This discrepancy comes from movie theater projectors, which in HD have a horizontal resolution of 4,096 pixels. Since the difference in pixels at this level is nigh imperceptible, both the industry and the vast majority of consumers have decided that 4K is easier to remember, market, and throw around conversationally. So 4K it is for both.
Now, let’s throw a wrench into the works.
As we move on down in our pixel count, our basis for classifying resolutions shifts on its axis. For much of Television History (up until our new friend 4K crashed the party), resolutions have been described in terms of vertical pixels rather than horizontal. When we refer to resolutions of 1080p, we are referring to the amount of vertical pixels in the display.
Having fun yet?
In a typical widescreen format a vertical pixel count of 1,080 would correspond to a horizontal count of 1,920 or 2K. So essentially you can think of a 1080p display containing one quarter the number of pixels and therefore one quarter the resolution of a 4K display.
Moving on down the aisle, if you’ve been around long enough (which isn’t that long at all, really) you’ve scoped a 720p display. Once the standard, these are becoming increasingly rare and most new TV’s on the market are 1080p at a minimum. Here again, 720 is referring to the number of vertical pixels. So we wind up with a ratio of 1280 x 720. This is about half the resolution of a 1080p image.
My humble advice: Don’t panic.
Ratios such as “half” and “one quarter” make it sound as if the differences in image quality must be stark. However, take a gander at this handy dandy chart put together by Carlton Bale:
As you can see, pixel count and resolution are fairly moot if either your screen is on the small side or your living room on the large (or both).
Also keep in mind that there are benefits and drawbacks to each pixel count, and resolution is by no means the single deciding factor in image quality. Consider the fact that both ABC and ESPN still broadcast their HD channels in 720p, and any Google search will turn up as many different explanations for this as there are pixels in the transmissions themselves.
This subject is as deep and as vast as you care to look into it. My hope is merely that you now have a better understanding of the naming conventions of most consumer level displays, and can make a more informed choice as to which resolution is right for you and your media. In future installments of the Pro Presenters blog we will address some of the other factors that contribute to overall image quality. In the meantime, I hope this provided you with a little bit more clarity (sorry, last one…I promise).