Pixel Pitch – What to Know Beyond The Viewing Distance

LED video walls are offered with a variety of shapes, sizes, and options to fit an extremely wide range of applications and environments. There is a multitude of LED video panel models available on the market that can be designed to cater to the specific needs of a unique application.
One of the greatest variations in an LED wall is the resolution, and it can be critical in defining how well it performs for its intended application. LED video walls utilize an array of individual RGB LEDs that are spaced out to display a vivid image on a large scale. Since the panels for an LED screen are designed to be modular for a multitude of screen sizes, the “resolution” for an LED video wall is measured differently than the average TV, projector, or LCD monitor. Rather, the resolution of an LED video wall is measured by Pixel Pitch.
What is Pixel Pitch?
Pixel pitch (also sometimes referred to as Dot Pitch) is the official unit of measure that defines the spacing between each LED pixel on the panel or video wall itself. The nomenclature for various pixel pitches is designated in millimeters. So the numbering defines how far apart, in millimeters, each pixel is from each other. The lower this number is, the closer the LEDs are to each other, the higher the display resolution as there is a greater density of pixels to make up the image.
[TIP: Pixel pitch is referred to in two ways, the number in millimeters (i.e. 3.9mm) or the P number (i.e. P3.9), they’re both used interchangeably, but mean the same thing.]
Pixel pitches can range all the way down to 0.7mm and all the way up to 100+ mm. That’s a lot of options to choose from and Yes, those low-res options do still exist today. We understand that nobody wants their investment to look pixelated. Video walls have gained in popularity because of their potential for stunning image quality that projectors and LCD monitors cannot achieve. That being said the right pixel pitch can be a critical factor in not only budget but also as to how your video wall performs for your application.
Pixel Pitch & Viewing Distance
The most common, and among the most important determining factor in calculating the right pixel pitch of an LED wall is the viewing distance. Every pixel pitch essentially designates how far the average viewer needs to be away from the screen in order to see a clear, non-pixelated image. The typical rule thumb is 1 meter of viewing distance for every millimeter of pixel pitch. The guide below represents the minimum viewing distance ranges for common pixel pitches.
Calculating the viewing distance and pixel pitch for an LED wall is only going to accomplish one thing, which is a clear picture to those viewing screen. The pixel pitch requirement can be entirely different depending on the environment specific to the application. While the viewing distance plays a vital role in selecting the right pitch for your LED screen, it should not be the sole calculating factor.
Pixel Pitches Beyond Viewing Distance
The purpose of this article is not to be another explanation of what pixel pitch is or what kind of viewing distance you need for your screen. Does pixel pitch play a role in cost? Yes, but with limitation. There are a variety of key performance factors and application-specific considerations that can come into play outside of the pixel pitch that can make or break the project/investment. There are many instances in which it may be necessary for a higher or lower resolution screen even if it’s outside the recommended viewing distance. There are some fine lines where even a fraction of a millimeter in pitch can make a considerable difference. It’s important to find the right balance so that your investment (or your client’s investment) will perform up to expectations.
The Other Considerations
Let’s take a deeper look into some considerations on how you can achieve the right balance on pixel pitch to ensure your video performs the way you need it to:
1. Detail of Content
Even though you can achieve a clear image by choosing the recommended pixel pitch for the minimum viewing distance, what about the finer details of your content? Each pixel plays a role in creating that image. From a big picture standpoint, the video wall can appear clear and HD as expected, but since the pixels are spaced further out, the finer details of your image such as small text or icons could become pixelated and potentially hard to discern by viewers. This can be especially true if you plan to display multiple windows on the screen simultaneously. The greater pixel density of a finer pitch LED wall would help to ensure those finer or smaller details are more discernable and ultimately result in a cleaner look.
2. Brightness
For outdoor LED screens, the LEDs require more power in order to see an image in broad daylight. The power supplies in LED video panels have a limit as to how much power is available to each and every LED pixel. When the pixel density is lower, more power is available to the LEDs to deliver a brighter output without significantly increasing power draw or requiring a higher wattage power supply. While it may be possible for higher resolution LED screens to achieve higher brightness levels, there may be compromises to optical quality, power-efficiency, and life expectancy of the LEDs.
3. Contrast Preservation
This applies more towards outdoor LED displays. When the pixel density is lower on an LED screen, there is more black spacing between the pixels. This can allow an LED wall to achieve higher contrast levels and more vivid imagery while maintaining a high brightness. Most LED pixels for outdoor use have a white face, which can be more reflective of sunlight. While the increase in spacing can absorb sunlight to make the image more visible. Black face LEDs can achieve higher contrast levels but come at a premium with a potential compromise in brightness.
4. Size & Native Resolution
Each LED pixel on an LED wall counts as 1px from your input source. LED walls don’t always follow the same native resolution standards most people are familiar with, which is why scaling is usually necessary for most projects. However, they do follow the same input resolution standards to display media content. For ultra-large screens, it can be easy for an LED wall to exceed 4K, 8K or 16K resolution with a pixel density that’s too high. This can require extensive processing power, require the user to have create custom content, and have a media server that can drive this kind of content. Which can significantly increase the overall cost beyond the increased cost of the LED panels themselves. With lower pixel densities, the entire input source can stay within a 1920 x 1080 or 3,840 x 2,160 canvas to display on the LED screen with simplified processing. This is also when one must consider how far a viewer needs to be standing to see the entire image across the LED screen rather than the closest distance they will be.
5. Field of Vision
LED Video Walls tend to be large. While we know how close viewers may be to the screen, we must also factor how much media content being displayed they will actually be able to see when at the closest possible distance. If the screen size and the media being displayed is larger than the viewer’s field of vision, while more detailed and less pixelated, the viewer may not be able to discern the full message or image the screen is conveying at the closest physical distance from the screen. This can create a difference between the minimum viewing distance and minimum physical distance from the screen.
6. Camera Environments
In environments where cameras are being used for video production, streaming, or broadcasting, the pixel pitch requirements for the camera are higher than the viewing distance. Cameras can show moire patterns and pixelation on an LED screen more than the naked eye. The requirements for an LED wall to show well on camera can be very strict outside of just the pixel pitch. In-camera critical environments, however, such as broadcast studios, virtual production, or environments where there are multiple shooting angles and focus points, a finer pitch LED screen is typically required in order to offer more content detail and less moire at closer focus points. Most LED video walls can show well on camera without pixelation, most stadiums for example use 10-12mm screens, so this factor will greatly depend on shooting, focus, and focal lengths.
The Bottom Line
All in all, when choosing the right pixel pitch, it can come down to a fine line about balance. Every environment and project is unique to itself, and while viewing distance does play the most critical determining factor in choosing the right pixel pitch, it’s important to consider all factors about your environment to ensure that the video wall serves its purpose and works the way you need it to. The project consultants at DVS are highly knowledgeable of a variety of industry markets and environmental applications to assist you in choosing the right pixel pitch so that your LED wall is just right.