Getting the best picture out of your HDTV, that you probably never knew. PART 1 Chances are high that the day you bought your new HDTV you were either too excited and impatient to go through the menu settings to adjust the picture settings to obtain a better picture quality, because you just wanted to plug in your Xbox 360, PS3 and/or Blu Ray player, and start drooling in all of the HD glory. And if this was your second or third set you most likely had the meh been there done that attitude. Even still, you may have tinkered around a bit and just cranked up the brightness, contrast and sharpness to near max. Am I right folks? Lets pretend Im right and get started shall we? Before we begin you should know what each of the basic settings actually do. Makes sense huh? Brightness: Alters the black levels on your TV, not the white!! So when you turn up the brightness in reality youre really just turning down the blackness. This control effectively determines what is known as the Black Level - the brightness or darkness with which blacks are presented. Higher values will result in a washed-out milky look to the image, while reducing black level too much results in what is known as Black Crush, deeper looking blacks at the cost of loss of detail in darker areas. Contrast or Picture: Opposite of brightness. This will turn down the white colors of the set as you go up in contrast. This control generally determines how bright the screen will be. It is also known as the White Level, in that it determines how bright whiter areas will appear. Its impact will differ on LCDs which have a separate Backlight brightness control. On such LCDs, the Backlight brightness setting determines the overall brightness of the screen, while Contrast will control how much detail is visible in white areas. Use a combination of both settings when conducting a white pattern test. Color: Adds saturation to all of the colors. This control is also known as Color Saturation, and controls how bright or dull colors appear to be. The higher the Color control, the richer the same color will appear. Sharpness: This control is widely misunderstood. Most people realize that it controls the crispness of the image, but dont fully comprehend that on an HDTV, it is an artificial technique which adds undesirable elements to the image to make it look sharper. As the Sharpness control is raised, the image is altered so that where edges are detected, subtle highlights are added around them to raise the perceived contrast around the edge. This makes edges look sharper, but it creates white halos around them and can also reduce detail in other areas of the image. Essentially, raising Sharpness doesnt draw out any more information from the video source. The amount of detail in the source remains constant. All Sharpness does is to highlight the more prominent details at the cost of loss of more subtle detail, along with the introduction of visual glitches. For this reason, it is recommended that Sharpness be set as low as possible. Tint: Really a non essential adjustment left over from the CRTs or old school TVs. It gives a green or magenta shade to the image. In most cases you wont ever have to adjust the tint. Gamma: Most HDTV now have this setting. If yours does not, dont worry. And even if it does, it shouldnt be adjusted unless you understand its complex nature. Known more formally as Gamma Correction, it basically determines the gradation of brightness on your TV - the amount of brightness for any particular level of light specified in the source. The reason Gamma exists is because of the way the human eye perceives light. Our eyes are much more sensitive to changes in lower levels of light than to the same changes in brighter areas of light. So while an imaging device like a camera typically has a linear (1:1 or straight line) relationship between light input and output, our eyes have an exponential (power or curved line) relationship, similar to Gamma. Source material such as movies take advantage of this property by encoding brightness to use more data at the darker end, and less at the brighter end. This results in more efficient use of RGB data, such that that an 8 or 10 bit color depth with Gamma encoding can be just as effective as 12 or 14 bit color depth without it - see the Color Reproduction section for details on color depth. On traditional CRT monitors, this special source Gamma encoding is automatically compensated for by the inherent input/output characteristics of CRT monitors; CRT monitors also have a non-linear relationship between voltage input and light output which is the opposite of the gamma encoding in the source, and the combination of the two cancel each other out to result in perceptually smooth gradation of brightness. An HDTV is not like a CRT however, and has a linear relationship between input and output. So a form of software Gamma correction is required on an HDTV to correct the source Gamma encoding into something which visually looks smooth. This is what the Gamma control on an HDTV does - it determines the shape of the exponential curve which applies to this Gamma correction. There is a lot of debate regarding the correct value for the Gamma control, but in practice the standard target is around 2.2 to 2.35. In plain English: setting Gamma too high will make the image generally darker than the source intended, and will reduce detail in dark areas, while setting the gamma too low will give an overly bright and washed out image. For correct image reproduction, set your Gamma control to the available option which is closest to the target range, either 2.2 or 2.4. This must be done in combination with the correct black level and white level as covered under the Brightness and Contrast controls further above to achieve a level of brightness gradation on your TV which is as the source material was intended to display. Color Temperature: This control determines the temperature of white, which according to the appropriate D65 standard should be equivalent to around 6,500 K (Kelvin), similar to ambient daylight at midday. If Color Temperature is overly warm, that is at lower color temperatures approximating less than 3,000 K, whites and greys will start to take on a yellowish or reddish tinge. At Color Temperatures above 5,000 K, also known as cool, whites and greys will progressively start to turn more bluish, especially around the 9,000 K mark. Using the correct Picture mode should get you close to the correct 6,500 K color temperature - typically this is a THX, True Cinema or Movie mode as discussed earlier. Color Temperature presets of Cool, Normal and Warm on some picture modes also allow you to set something close to an accurate level by selecting the Warm or low value. However because most people are used to a cooler and slightly bluish temperature for white, this may look incorrect and slightly reddish at first. You will need to allow your eyes to adjust, and if you still have doubts, try the Normal or middle value as a compromise. Image Processing: There are a multitude of options on any modern HDTV designed to ostensibly improve the image by manipulating it in one way or another. The same option may also vary in name from brand to brand, as some manufacturers give them proprietary titles. As such, there are too many of these options to individually cover in this guide. The general rule is this: turn off as many of these image processing enhancements as you can, because with few exceptions, they will reduce image quality rather than improve it. This is because they are all post-processing features, so called because they apply image processing after the source image has been received in the TV, altering the source from its original form. You should of course experiment to see what each option does, and refer to the manual and do further research for details, but again, the majority of these extra features can and should be turned off. Below are a few of the more common image processing options you may find: Edge Enhancement - Also known as Resolution Enhancer or a similar such name, is much like your Sharpness control as covered earlier. You can experiment with using it at a mild setting if you find a poor source to be overly blurry, such as low quality Digital TV broadcasts. Otherwise it is best left Off. Noise Reduction - Also known as P-NR or DNR, can similarly be used on a mild setting on very poor sources such as excessively grainy old films to smooth (blur) the image slightly, but again, it is best left off if you dont want to lose detail in the image. Color Enhancement - Options such as Vivid Color, Deep Color and the like will extend the color gamut and oversaturate the image, resulting in a loss of natural tones. None of the common sources such as Blu-rays or DVDs can actually use an extended color gamut. You can experiment with these options if you wish, but for strict color accuracy turn off all such color enhancements. Motion Smoothing - These options come under a wide variety of proprietary names. If running a plasma you should disable all forms of motion interpolation or motion smoothing to avoid an artificially smooth look to motion. On an LCD, you may need to keep some level of motion interpolation enabled if motion on your TV looks blurry or undesirable without it. In Part 2 well provide a link to download an excellent free DVD you can burn to apply this knowledge. It features all the test patterns you will need to get the best picture out of your HDTV.
Posted on: Tue, 15 Oct 2013 20:19:23 +0000