Easily calculate the ideal viewing distance for your visitors

The use of screens during a conference or event has been indispensable for decades, whether they serve to display presentations, digital posters, signage or as comfort monitors for presenters. Yet a common problem is that the information on those screens is not always easy to read for visitors. This is often because the distance from the screen to the visitor is too far, making small details difficult to see. This is not something you want, as important information may not be legible. Fortunately, that problem is easily prevented; there is a formula that calculates exactly what the ideal screen size is for the viewing distance of your visitors.

It is important not to sit too far from a screen, however sitting too close to a screen does not feel pleasant either. In the past it was often said, that sitting too close to a screen was bad for your eyes, nowadays this is less true. The latest screens have a much sharper display, even at close range. Too close is still not good aesthetically, because then you will see the pixels (image points), but it is no longer as harmful. The recommended viewing distance to the screen therefore depends on both the screen’s diagonal size and the resolution. The most common resolutions are explained below.

Full HD

Almost every new display nowadays has a minimum resolution of 1920 x 1080 pixels, also known as Full HD. If you want to calculate the optimal distance for a display or projection screen with Full HD resolution, you can basically multiply the height of the display in centimeters by a factor of 6,5. There is however, a third factor that influences the viewing distance, namely the content that will be displayed on the screen. For example, there is a big difference whether it concerns a PowerPoint presentation, one or more PiP (Picture-in-picture) images, or just enlarging the speaker image. In the latter case, you can safely sit a few extra meters from the screen. At ACS we use the rule of thumb of 8 x the width of the screen in centimeters.

If your visitors are further away from the screen than the ideal viewing distance, then a larger screen is desirable.

4K

A 4K screen has a resolution four times larger than one with Full HD quality. A higher resolution means more pixels per square centimeter. This means there is less space between the individual lights, which ensures that a 4K screen looks much sharper up close. If the participants are seated near a (large) screen, we recommend a screen with a higher resolution. However, at a relatively great distance, the difference is negligible and the added value of the extra pixels is no longer the case. The same goes for screens with even higher resolutions such as 8K.

For both 4k and 8k displays, all the material that is shown must be formatted in this high resolution and the source (usually a laptop or media server) has to be able to supply this signal.

Delay screen(s)

If a room is of such size that the required size of the main screen in the front of the room is difficult to realise, then one or more delay screens are a simple and affordable solution. A delay screen is a screen used to duplicate what is being shown in the front of the room to visitors who are considered too far from the original source. Regarding viewing distance the same rules apply as above, so look carefully at the size and resolution of the screen and the content that will be displayed. Try to find a good balance between what is ideal and what is comfortable!