The white point in color definitions is probably one of the least known parameters on a display’s spec sheet. Because what does it even mean? White is white, no? Most people know it is the combination of all wavelengths of light. So how come different settings exist in the market? The reason is that the theoretic value of white is never seen in reality. If you look at a white piece of paper for example, it will be colored by the light source that shines on it. In other words it will look different when you look at it under sunlight conditions, than under artificial light in your office. The same goes for displays. However, the cool thing is that we can often choose the white point of the display. Tampering with the white point setting will consequently impact and define the mood of the image. Note that for convenience we will be talking about displays in this article, but the same goes for just about any visualization device, including projectors and direct view LED tiles.
If you have ever looked more closely to display settings, you will probably have noticed that the most commonly used white points are 5000K and 6500K. The ‘K’ stands for ‘Kelvin’, and is indeed the official unit to indicate temperature (with 0 Kelvin being -273.15°C or -459.67°F). So that’s where the term ‘color temperature’ comes from. But why is the actual temperature unit used for this? Aha, that’s where we come to the interesting part…
So how does this connect to the settings of your display I hear you say? As said, absolute white is just a theory and never seen in reality. A display works with a light source, which has a slight native hue to it. This native white point is commonly indicated in the display’s specifications. However, advanced software can change this hue, and match it to different temperatures on the Kelvin scale. This is not an absolute match (don’t worry, your display is not as hot as a gas burner), but a measure of the color hue of white light, corresponding to the color that would be emitted by a hypothetical black body.
However, the white point setting is important if you are a professional designer or creator. Then it is best to set the white point as close as possible to the destination of your work. If you are a graphic designer, and your work will be used in print, then 5000K is a good choice. This corresponds best with the common lighting conditions for reading printed materials, and is a yellowish version of white. However, if you are designing for the internet, then 6500K is a better option as displays commonly have a higher white point. Just drive around in the evening and look at the light of the TV screens or computer monitors you see. It is dominantly blue, because this bluish color setting is the default for computer screens. This is the same for movies made in the USA or Europe. Japanese movies, on the other hand, are shot for 9300K.
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A special kind of white point selection is used in control rooms, where the color temperature changes throughout the day. In night mode, the amount of blue colors will be diminished, to prevent eye strain.
Barco’s unique Sense X automatic color and brightness calibration system, also allows white point adjustments. You can freely select the white point to any color temperature between 3200K and 11000K. This system is available on Barco’s rear-projection video walls (both LED-lit and LASER-lit) and LCD video walls. This gives you the flexibility to precisely select the mood of the image you want.
Although the white point is not the best known specification for many users, it can sometimes make a huge difference in the display’s performance. Especially in environments where a certain ‘mood’ is to be set with the screen, it is essential to select the best suited white point.