Monitor calibration which white point

Japanese movies, on the other hand, are shot for K. For many displays, you can define the white point although it is not always called this way. Sometimes you can choose between some standard values commonly K, K, K and K or you can select the white point yourself from K to K in steps of K.

For consumer televisions for example, you can select the color temperature to be more red or more blue which is equivalent of selecting the white point. Only professional users, for whom color is crucial as the display should show the image as it is intended to be seen, calibrate their screens.

Also reference monitors used in film production for example, are calibrated. You can thus define the white point. But in which environments is this really needed? Many users will play around with the setting at first installation, but then leave it in the selected position. However, in some environments an exact white point is crucial. For example, when the display or video wall is used as a broadcast studio backdrop, the white point determines the mood of the complete broadcast.

This means a lot of attention is given to this spec. 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. You can freely select the white point to any color temperature between K and K. This gives you the flexibility to precisely select the mood of the image you want. Its release coincided with the introduction of the Apple Laserwriter, the Linotype Linotronics imagesetter, and Aldus Pagemaker, the first page layout program.

All of these components were tied together by the PostScript page description language, also released in by a fledgling company called Adobe. This launched the desktop publishing revolution of the mids and beyond. It was no coincidence that Apple chose a system gamma that was geared towards print output. Windows PCs, on the other hand, have never had built-in gamma correction, although this is an option on some graphics cards.

This reflects the fact that PCs were always targeted towards business and the mass consumer market rather than to graphics professionals. With no hardware correction, the Windows system gamma is about 2. With the release of Mac OSX They did this, of course, to ensure that video games and web images looked the same on Mac and PC systems. In doing so, however, they abandoned their traditional base of support among graphics professionals.

The choice of gamma settings, therefore, is no longer dictated by the computer platform or operating system. Instead, when calibrating your monitor, you can choose a gamma setting that is best suited to the type of work you normally do. This will override the built-in settings of the system. If you create mostly images that will be viewed on screen — for the web, PowerPoint, video games, etc. This will help ensure that your images look consistent across the widest range of computers used in business and the mass consumer market.

On the other hand, if you still create most of your work for print as I do , stick with 1. Not only is this setting more compatible with high-end printing system, it also produces noticeably lighter images on screen.

This helps you see detail in shadows, something that is critical when creating and editing digital images. The other important setting when calibrating a monitor is the color temperature, sometimes called the white point because it affects the appearance of white on screen.

Several scientists in the late s noted that cold, black objects radiate different colors of light as they are heated to high temperatures. This led to the development of the tungsten filament light bulb.

In , Max Planck proposed the idea of an ideal black body, a hypothetical object that reflects absolutely no light but radiates different wavelengths of light with increasing temperature.

Although the ideal black body only exists in theory, Planck was able to determine mathematically the wavelengths i. At relatively low temperatures, the black body would glow red, then orange, then yellow.

At very high temperatures it would radiate a bluish light. This is quite different from our emotional associations with different colors. We think of blue as being cool, while yellow, orange and red are warm colors. You can confirm this by looking at a gas flame. The center of the flame — the hottest part — glows blue. The cooler outer edge of the flame glows yellow and orange. This is just a different scale for measuring temperature, like Celsius and Fahrenheit.

The Kelvin scale is noteworthy because zero degrees on the Kelvin scale is known as Absolute Zero — the temperature at which all molecular motion stops equal to So what does this have to do with monitor calibration? There is no such thing as pure white.

Every light source has a slight hue or color cast to it. The color profile specifies the target settings from your calibration, such as gamma, white point and luminance, in addition to measurements from the calibration, such as the maximum red, green and blue intensities that your display can emit.

These properties collectively define the color space of your monitor. A copy of the LUT is also included, but this is not used directly since it's already been implemented by your monitor or video card. A color profile is used to convert images so that they can be displayed using the unique characteristics of your monitor.

Unlike with the LUT, you will need to view images using color-managed software in order to use a color profile. This won't be a problem if you're running the latest PC or Mac operating systems though, since they're both color-managed. Otherwise Photoshop or any other mainstream image editing or RAW development software will work just fine. Whenever a digital image is opened that contains an embedded color profile, your software can compare this profile to the profile that was created for your monitor.

If the monitor has the same range of colors specified in the digital image, then values from the file will be directly converted by the LUT into the correct values on your monitor. However, if the color spaces differ as is usually the case , then your software will perform a more sophisticated conversion.

This process is called color space conversion. Do not assume that just because you've performed a color calibration that this monitor will now reproduce accurate color without complication.

It's important to also verify the quality of this calibration. If you end up noticing that your color calibration device was unable to repair some inaccuracies, at least you can be aware of these in the back of your mind if you perform any image editing that influences color.

The quickest and easiest way to diagnose the quality of a color calibration is to view a large grayscale gradient in an image viewing program that supports color management. Sub optimal monitor calibration may render this gradation with subtle vertical bands of color, or occasional discrete jumps in tone.

Move your mouse over the image below to see what a poor quality monitor calibration might look like :. Example of a smooth grayscale gradation for diagnosing the quality of a monitor calibration. Such a gradation is easiest to diagnose when viewed at your display's maximum size, and when alternating between having the monitor's color profile turned on and off.

When "Monitor RGB" is turned on, this means that the monitor's color profile is not being used. If color banding is visible, then this might mean that your monitor needs re-calibration. It's generally recommended to perform this once every month or so, depending on how important color accuracy is to your work. Alternatively, your monitor's native color reproduction might be so far from optimal that the color profile represents an extreme correction.

This could be due to the monitor calibration settings you're using, but could also be caused by the age of the monitor. In the latter case, a color profile is likely still a vast improvement over no color profile — but it comes with compromises. Unfortunately, there are limits to how accurately you can calibrate your display.

Fortunately, the bit depth of your monitor's internal LUT can influence how well it is calibrated, since a monitor with a higher bit depth LUT is able to draw upon a larger palette of colors:. Note: A higher bit depth internal LUT does not mean that a monitor can actually display more colors at the same time , since the number of input values remains the same.

This is why a higher bit depth LUT in your video card will not on its own achieve more accurate calibrations. In the low bit depth example, the brightest 4 and darkest 1 shades are forced to merge with white 5 and black 0 , respectively, since the LUT has to round to the nearest output value available. On the other hand, the high bit depth LUT can use additional intermediate values.

This greatly reduces the likelihood of color banding and image posterization — even when the display is old and deviates substantially from its original colors. Aside from making screen-to-print matching hard, this reduces the monitor lifespan. You need a calibration device to measure the luminance of your monitor and always return it to the same level, as the backlighting slowly degrades. The trouble with using onscreen monitor settings to do this e. Most monitors can reach that level using the OSD brightness control alone, without resorting to reducing RGB levels and gamut.

The setting you use is not critical unless you are explicitly trying to match the screen to a print or print-viewing area. The monitor should be the brightest object in your line of vision. Some calibrators will read ambient light and set parameters accordingly. In controlled situations, this feature is needless and even unhelpful. Many printers set their monitor luminance very low. The idea is to hold a blank piece of printing paper up next to your screen and lower the luminance until it matches the paper, or just set a low level so that this is more likely.

Potential downsides include a degraded monitor image since not all monitors can achieve this low luminance level without ill effect. Still, you could try it. This is about finding what works for you and your gear.

Another way printers set monitor luminance is to match it to the lighting of a dedicated print-viewing booth or area. As well, print display lighting is always adjustable in its intensity.