The main purpose of the RGB color model is for the sensing, representation, and display of images in electronic systems, such as televisions and computers, though it has also been used in conventional photography. Before the electronic age, the RGB color model already had a solid theory behind it, based in human perception of colors.
BasICColor Display 570 Build
Typical RGB input devices are color TV and video cameras, image scanners, and digital cameras. Typical RGB output devices are TV sets of various technologies (CRT, LCD, plasma, OLED, quantum dots, etc.), computer and mobile phone displays, video projectors, multicolor LED displays and large screens such as the Jumbotron. Color printers, on the other hand are not RGB devices, but subtractive color devices typically using the CMYK color model.
Before the development of practical electronic TV, there were patents on mechanically scanned color systems as early as 1889 in Russia. The color TV pioneer John Logie Baird demonstrated the world's first RGB color transmission in 1928, and also the world's first color broadcast in 1938, in London. In his experiments, scanning and display were done mechanically by spinning colorized wheels.[10][11]
One common application of the RGB color model is the display of colors on a cathode-ray tube (CRT), liquid-crystal display (LCD), plasma display, or organic light emitting diode (OLED) display such as a television, a computer's monitor, or a large scale screen. Each pixel on the screen is built by driving three small and very close but still separated RGB light sources. At common viewing distance, the separate sources are indistinguishable, which tricks the eye to see a given solid color. All the pixels together arranged in the rectangular screen surface conforms the color image.
During digital image processing each pixel can be represented in the computer memory or interface hardware (for example, a graphics card) as binary values for the red, green, and blue color components. When properly managed, these values are converted into intensities or voltages via gamma correction to correct the inherent nonlinearity of some devices, such that the intended intensities are reproduced on the display.
For images with a modest range of brightnesses from the darkest to the lightest, eight bits per primary color provides good-quality images, but extreme images require more bits per primary color as well as the advanced display technology. For more information see High Dynamic Range (HDR) imaging.
In classic CRT devices, the brightness of a given point over the fluorescent screen due to the impact of accelerated electrons is not proportional to the voltages applied to the electron gun control grids, but to an expansive function of that voltage. The amount of this deviation is known as its gamma value ( γ \displaystyle \gamma ), the argument for a power law function, which closely describes this behavior. A linear response is given by a gamma value of 1.0, but actual CRT nonlinearities have a gamma value around 2.0 to 2.5.
Similarly, the intensity of the output on TV and computer display devices is not directly proportional to the R, G, and B applied electric signals (or file data values which drive them through digital-to-analog converters). On a typical standard 2.2-gamma CRT display, an input intensity RGB value of (0.5, 0.5, 0.5) only outputs about 22% of full brightness (1.0, 1.0, 1.0), instead of 50%.[19] To obtain the correct response, a gamma correction is used in encoding the image data, and possibly further corrections as part of the color calibration process of the device. Gamma affects black-and-white TV as well as color. In standard color TV, broadcast signals are gamma corrected.
In color television and video cameras manufactured before the 1990s, the incoming light was separated by prisms and filters into the three RGB primary colors feeding each color into a separate video camera tube (or pickup tube). These tubes are a type of cathode-ray tube, not to be confused with that of CRT displays.
Photographic digital cameras that use a CMOS or CCD image sensor often operate with some variation of the RGB model. In a Bayer filter arrangement, green is given twice as many detectors as red and blue (ratio 1:2:1) in order to achieve higher luminance resolution than chrominance resolution. The sensor has a grid of red, green, and blue detectors arranged so that the first row is RGRGRGRG, the next is GBGBGBGB, and that sequence is repeated in subsequent rows. For every channel, missing pixels are obtained by interpolation in the demosaicing process to build up the complete image. Also, other processes used to be applied in order to map the camera RGB measurements into a standard RGB color space as sRGB.
With the predominance of 24-bit displays, the use of the full 16.7 million colors of the HTML RGB color code no longer poses problems for most viewers. The sRGB color model (a device-independent color space[23]) for HTML was formally adopted as an Internet standard in HTML 3.2,[24][25] though it had been in use for some time before that. All images and colors are interpreted as being sRGB (unless another color space is specified) and all modern displays can display this color space (with color management being built in into browsers[26][27] or operating systems[28]).
The Color Calibration wizard will now provide some suggestions on how to adjust the display features using the built-in controls (on-screen display menu) provided by the display device. Once you have successfully completed this task, click Next.
The next prompt will allow adjusting the gamma values of the display device. Gamma controls adjust the brightness of the Red, Green and Blue (RGB) color values. A sample image of a good gamma setting is provided below. Click on Next to begin this process.
The wizard will now move on to adjusting the brightness and contrast of the display. This is done using the display's On-Screen controls. Click on Next to proceed. Note! Depending on the display device being used, you may not have these controls available to you. In this case, click Skip brightness and contrast adjustment and proceed to step 10.
Target for calibration is a 2.2 Gamma value, with a White Point at 6500K and a Brightness value set at 120 cd/m2. Calibrated values are then analyzed with the Spyder5ELITE Display Analysis tool. Do note that Dynamic Contrast Ratio and other extra features built within the OSD are disabled during the tests. The following OSD values are selected for the display calibration.
Motion Picture Response Time (MPRT) is the numbered approach to demonstrate the level of perceived motion blur on a display. Basically, a lower persistence value indicates less motion blur. Refresh rate and the sampling method plays a major part here whereas a higher refresh rate nominally features better display persistence values.
Setting up a pursuit camera courtesy of Blur Busters allows us to a great extent, perceive the actual motion clarity of the display. Using such method also allows us to check out motion artifacts including ghosting, inverse ghosting and blurring. This pursuit camera test is a peer-reviewed invention.
Back light Bleed is the phenomenon where back lighting from a display leaks. This is prevalent with displays where LEDs used to light the panel are situated at the edges of the display. Testing the back light of the display is conducted on a dim room, simulating the recognizable amount of bleed for such scenario.
Viewing angles are also tested to check out how the display panel performs at different positions or eye levels. This should be helpful if you are looking for a panel that could be used on multi-monitor setups.
Frame Skipping is the phenomenon where dropped frames and missing refreshes occur due to ineffective refresh rate overclocking. We are are utilizing the Blur Busters Frame Skipping Checker to test if there is any. If your display exhibits such issues, it should be perceptually similar to in-game frame skipping.
When it comes to build quality, the BenQ SW320 does not disappoint. Although it has rather thick bezels, making it not a very good candidate for a multi-screen setup (tough to imagine anyone putting two of these in typical room or office space), the display itself feels very well-made; not like a cheap, consumer-grade plastic monitor. Aside from the power button on the bottom right, there are five more buttons that are used to navigate the on-screen display (OSD). The buttons are standard push-style buttons, not touch-sensitive ones that you can find on some modern monitors. The screen itself has a nice matte coating that is supposed to do a good job at reducing reflections and glare.
The BenQ SW320 has a total of 3 input ports for connecting your devices: one HDMI 2.0, one DisplayPort 1.4 and one Mini DisplayPort 1.4. While it is nice to have these connection options, I wish the monitor had more than one HDMI port and it would have also been nice if there was a USB Type-C / Thunderbolt connection option. Interestingly, the smaller and the less expensive BenQ SW271 has these options, but not this big guy. It was not a problem in my environment, but if you want to hook this display up to an iMac or a MacBook laptop, you will need to get an appropriate cable or a Thunderbolt to DP or Mini DP adapter. With everything going USB-C, it makes sense for BenQ to include it in the future iterations of this monitor.
The next step was to click Start Measurement, put the colorimeter in the middle of the screen and start the calibration process. At the start of the process, the software first erased the existing LUT on the display:
Aside from difference in measured vs display profile whitepoint (colorimeter measured 6900K), everything else checked out pretty well. Average delta was around 0.57, while the maximum was at 1.39, also within acceptable range. Looks like BenQ does a good job with factory calibration, so if you want to get started quickly, using the AdobeRGB color mode (default) will surely get you started. Just make sure that you adjust the brightness levels accordingly. By default, mine was set to 150 cd/m2, which was a bit too bright for my taste, so I manually adjusted it to 120 cd/m2 in DisplayCAL before verifying the results. 2ff7e9595c
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