|Sony KDL-46Z4100 LCD HDTV|
|Home Theater Flat Panel HDTVs LCD HDTVs|
|Written by Tom Volotta|
|Thursday, 30 April 2009|
Page 8 of 9Special Color Processing
Consider the KDL-46Z4100 a slightly lesser version of the 2008 model of the 46XBR6, rather than an upgrade from its S, V and W non-XBR siblings. On the outside, the 46Z4100 and 46XBR6 could be mistaken for twins, having nearly the same form factor, with only minor cosmetic differences, most noticeably the XBR6 accentuates its floating sound bar beneath the LCD panel and offers optional grill covers in four colors at an extra cost. However, the critical similarities that couple the Z4100 and XBR6 while distinguishing them from the S, V and W models are really a powerful grouping of image processing and display technologies.
Both have 10-bit video processing and 10-bit LCD panels, x.v.Color™, Deep Color, High Definition Multimedia Interface (HDMI) 1.3 interface, the same BRAVIA Engine 2, WCG-CCFL Backlight, 120Hz Motionflow™, a full assortment of input/output, network and media connections and other key performance capabilities where it really counts. The XBR6 does have better dynamic contrast ratio and adds a built-in 11-watt subwoofer (always a nice touch) to its standard audio speakers.
But a few of the most advanced features also carry some question as to their practical expression of what you’ll actually see on the screen. Among the specifications for HDMI version 1.3-compliant equipment are the requirements to transport what is known as Deep Color and the xvYCC gamut.
x.v.Color™ is Sony’s brand name, now being adopted by much of the industry, for the xvYCC color standard. It is an expansion of the color spectrum that can be accurately created, processed and shown by cameras, recorders, players and display devices. x.v.Color nearly doubles the range the sRGB gamut, or Color Space, currently being used as the reference standard for HD television.
Where x.v.Color enlarges the available colors video technology can reproduce, Deep Color increases the precision which colors can be shown in a range from very saturated color to white. This capability depends upon the contrast ratio, the number of shades of gray from black to white, that can be reproduced as a smooth ramp of dark to light without drastic changes called banding. The greater number of shades of gray, the smoother and more natural the image will be. Color information is then mapped onto that grayscale foundation to produce corresponding hues.
In digital video, this smoothness or precise is determined by the bit-depth of the hardware and software used to create, transport and display the content. Since 1-bit (a state of On or Off) = 2 colors (black and white), if the technology supports 8-bits, 256 possibilities (28 = 256), or shades of gray from black to white, are able to be generated.
When each of the three primary colors of Red, Green and Blue are mapped onto its own 8-bit, 256 level grayscale, the result is a palette of nearly 17 Million (256 x 256 x 256 = 16,777,216) possible colors. Because the 8-bit depth precision is being applied to three colors, this is referred to as 24-bit color, or 24-bits per pixel and is known as True Color. But True Color is not Deep Color. Deep Color requires at least 10-bits of precision, and as such yields four times (210 = 1024) the 256 gradations of 8-bit. When mapped to RGB, a palette of over 1 Billion (1024 x 1024 x 1024 = 1,073,741,824) colors.
One of the most frequent times this banding occurs on television is on shots where there are natural extremes of contrast gradations such as the sky and underwater scenes appear with distinct bands of color rather than a smooth transition from saturated to light. Another common instance is the use of a graphic background (often gray) ramping from light to dark, typically used in commercials with an overlay of a company logo, product shot or announcing a special sale price.