Automatic Brightness control - DisplayMate

This difference of properties on two sides of paper is known astwo-sidedness.
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How to Control the Brightness of Your Computer With …

Manufacturers will normally quote a maximum brightness figure in their display specification, but it is also important to consider the lower range of adjustments possible from the screen as you would probably never want to use it at its highest setting.

Lot of parameters in paper surface like roughness, gloss, ink absorption, whiteness, brightness affect this.
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Luxeon Star High Brightness LEDs

The raw LCD panel hardware first needs to be adjusted andcalibrated at the factory with specialized firmware and software data that aredownloaded into the device in order for the display to produce a usable image –let alone an accurate and beautiful one. This is actually a science but mostmanufacturers seem to treat it as if it were a modern art form, so few Tablets,Smartphones, and even HDTVs produce accurate high quality images. The iPad miniactually has an excellent and accurate calibration considering its small ColorGamut (below) because each unit receives individual display factorycalibration. Each Kindle Fire HDX 7 also receives individual unit displaycalibration for the Color Gamut and White Point. For the Nexus 7 we don’t haveany specific calibration information.

To easilyverify this behavior with your own iPhone turn On Auto-Brightness underSettings and set the Brightness slider near the middle of its range.
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is another oft-quoted but not-fully-understood metric which is a critical element of good image quality. The ability to create darker blacks allows a TV to have a higher contrast ratio, a term which will be explained shortly. The darker the blacks, the greater the appearance of depth and richness in the image shown. Black level is actually not particularly complex; it's just a measure of the level of brightness of a display when showing video black. It usually has as a very low luminance value, such as 0.004 fL (0.013 cd/m2), but rarely reaches 0.0 cd/m2/fL (true black) because most HDTVs can't achieve this.

How to Control the Brightness of Your Computer With Windows 7. This wikiHow teaches you how to raise or lower your computer's brightness on Windows 7 …
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Experiment with an electronics kit

In this Results section we provide Highlights of thecomprehensive Lab measurements and extensive side-by-side visual comparisonsusing test photos, test images and test patterns that are presented below. The section summarizes the Lab measurements in the following categories: , , , , , , . You can also skip the Highlights and go directly to the .

Build circuits with batteries, resistors, light bulbs, and switches

In order to achieve darker blacks and whiter whites, which in part justify these unrealistic figures, a technique known as Dynamic Contrast Ratio is now frequently used in HDTVs. The way it works is that the display constantly alters the brightness of the entire image, reducing screen brightness for scenes which are predominantly dark, and increasing the overall brightness for scenes which are mostly bright. The true measure of contrast ratio, also known as Static or Native Contrast Ratio, should provide the difference between the darkest and brightest luminance possible - and most displays don't have native contrast ratio capabilities anywhere near the dynamic contrast ratio numbers. A dynamic contrast ratio has several unwanted side-effects, including greyer blacks in bright scenes, and washed out whites in dark scenes. Additionally, depending on how it's implemented, the constant shift in overall panel brightness may become noticeable to the viewer, resulting in what's often described as Floating Blacks, Fluctuating Brightness or Fluctuating Gamma.

Pulse Width Modulation (PWM) - TFTCentral

From this discussion we can gather an important fact: most HDTVs, whether LCD or plasma, now use some type of dynamic contrast ratio. This can have annoying side-effects, and can render contrast ratio figures meaningless. So how does someone make sense of all of this? The answer is to take into account your viewing environment, combined with the measured black level and maximum luminance of a display as typically given in reviews. These factors will be sufficient to make a determination, as explained below.

Mini Tablet Display Technology Shoot-Out

Now that we understand the way HDTVs can display brightness and the lack of it on the screen, it's time to look at a metric which is supposed to show the range between these extremes on any TV. measures the difference in the luminance between the whitest image and the darkest image that a display can show. It's usually presented in a format such as 4,000:1 - this example would indicate that the whites on this display can be up to 4,000 times brighter than the blacks. The main benefit of a high contrast ratio is that in a scene containing both bright and dark elements, a TV can reproduce both elements correctly. That is, the dark areas will look suitably dark, while the bright areas will remain bright. Displays with poor contrast ratios will give more of a "washed out" image due to less of a difference between dark and bright areas.