|  | | Wide Color Gamut Displays |
Recent technology advances in digital image acquisition, color-processing systems, color printers, and other photographic I/O devices have been little short of remarkable. As well as startling resolutions, the range and depth of color reproduction has also shown significant improvements. A standardized color space promises the benefit of guaranteed color reproduction across all digital platforms and devices from the point of acquisition to the point of delivery, over a wide range of colors. As a simple example, a digital camera will take a photograph, which is then digitally transmitted to a PC running a photo editor application, and then sent directly to a printer. Ideally, the user will see the image on the electronic display, or as a hardcopy print-out with colors that are identical to the original. Traditionally a standardized color space, with a wide color gamut, has required sophisticated hardware technology and is generally found only in professional DTP, pre-press, color proof matching or color management system environments.
There have been alternative color spaces, with reduced palettes, which offer compatibility to a wide range of consumer devices. The most wide-spread is called sRGB, which is a color space standard defined by the IEC61966-2-1 (International Electrotechnical Commision). It is well promoted and wide-spread in consumer electronic applications, such as digital cameras, PC operating systems, PC color monitors, and desktop printers.
Specialist imaging devices, users of industrial 4-color printing presses and professional in the DTP and color-proofing industries have much more demanding requirements, and are looking for consistency across a large color space. Adobe RGB is an extended color space, promoted by Adobe, and which over time has become a de-facto standard in the professional color processing market. Through its wide-spread adoption, compliance with the Adobe RGB color space ensures cross compatibility with a wide-range of high-end professional digital color devices, cameras, scanners, digital transmission and printing process systems. However, due to the onerous requirements, compliance has been virtually impossible for most electronic displays; the digital chain has been in-complete.
The technical challenge has been to develop electronic display technology that complies with the Adobe RGB color space, and ensures complete color confidence in all aspects of color processing. The start of the digital chain, i.e. image acquisition, has successfully adopted the Adobe RGB color space, and printing or hardcopy printing technology has been able to follow suit. Display technology has now caught up with NEC-Mitsubishi offering leading-edge solutions in the key display technologies.
CRT Wide Color Gamut Display
The color gamut of a CRT display depends on the chromaticity of luminescence of each phosphor material red, green, blue. CRT displays have historically been able to show up approx. 85% of the NTSC (National Television System Committee in North America) color space, which defines which colors can be shown on a television. The weakness has typically been with using a green phosphor, which has simultaneously extended the color space and also featured a short persistency. The NEC-Mitsubishi 22" CRT model RDF225WG represents an exciting development in material science in bringing an Adobe RGB compliant display successfully to market, as well as offering the traditional Diamondtron Naturally Flat strengths of superb image geometry, clean focus and excellent ergonomics. The key materials-science innovation has been to develop a new low-persistence green phosphor, which can extend the display color gamut to a close approximation of the Adobe RGB color space.
| Item
| | Specification
| | CRT
| | 22" Diamondtron NF wide color gamut CRT
| | Aperture Grill Pitch
| | 0.24mm
| | Maximum Resolution
| | 2048 x 1536
| | Maximum (Peak) Luminance
| | 100 cd/m2 @ 9300K
80 cd/m2 @ 6500K
| | Color Gamut
| | Adobe RGB (93.3% to NTSC)
| | White Color Temperature Range
| | 5000-9300 K
| | Input Video Signal
| | Analogue VGA (infinite gradation)
| | Display Output Gradation
| | Analogue (infinite gradation)
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The RDF255WG has been successfully launched in the Japanese market by NEC-Mitsubishi Electric Visual Systems to customers with dedicated pre-press requirements. In Europe the model is available on a BTO (Build to Order) arrangement, with the expectation that the professional color processing market is focused on the wide gamut LCD displays.
LCD Wide Color Gamut Display using LED backlight technology
LCD technology as a display platform is clearly the dominant force in the display market due to the excellent ergonomics, reduced energy needs, space-saving and low cost of ownership benefits. New developments now mean that even LCD monitors can benefit from wide color space applications, which have been historically filled by CRTs. The principle of operation of an LCD is based on placing a bright white-light source (typically a mercury-filled fluorescent tube) behind a series of color matrix LC filters. The LCD filter matrices are digitally switched to adjust the light through-put, and therefore generate an image. The backlight itself has always defined the color temperature and color space available, which has typically been approx 75% of NTSC. However a new backlight consisting of LEDs (Light emitting diodes), which generate white light with an enhanced color spectrum, now allow a wider range of spectral colors to be displayed. On top of this, the LED backlight allows for tuning of the white point, which when allied with a feedback sensor ensures the display operates consistently to a pre-defined performance. This innovative solution has been adopted by NEC-Mitsubishi in close development cooperation with professionals from the color industry. The Adobe RGB color space can now be consistently reproduced with a LCD monitor!
| Item | __ | Specification | | LCD
| | 21.3" LCD with Dual Domain In Plane Switching
| | Dot Pitch
| | 0.27 mm
| | Resolution
| | 1600 x 1200
| | Color Gamut
| | 101% Adobe RGB (97% to NTSC)
| | Native White
| | 6500 K
| | Typical Brightness
| | 180 cd/m2 @ 6500K (typical)
| | Contrast Ratio
| | 500:1 (typical)
| | Input Video Signal
| | Analogue VGA and Digital DVI
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The wide gamut LCD display is in an advanced level of development, and current engineering prototypes indicate that the technology will be in mass production by early 2005. In the meantime NEC-Mitsubishi will be showcasing this cutting-edge technology to potential customers and preparing for the much awaited and exciting launch.
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