Goodbye to my CRTs
Last month, I made a trip to the recycling center to get rid of two CRTs. One was a TV receiver, the other a computer monitor. I finally crossed over to the dark side of LCDs — well not that dark, more gray. Since losing the CRTs, I have been pondering on the artifacts. The CRT workstation monitor had been in use alongside an LCD for years. I was never able to align them to match, especially on gray-scale tracking, even though I used a probe to set them up. I prefer the “look” of the CRT for Photoshop work, but its big drawback is the physical depth of the monitor. To achieve the recommended viewing distance, I needed a table behind my desk to support it. The LCD sits just fine at the back of the desk.
As for the TV, there are more artifacts, mainly because the pictures are processed by a scalar, and I am viewing moving images. Some content causes problems with the scalar, including diagonals and small regular patterns like brickwork. When I bought the LCD receiver, I had seen many examples, and I didn't like the “sample and hold” effect that is inherent in an LCD. It accentuated motion judder. The display I purchased runs at 100Hz and uses a form of frame interpolation. It does work; I am not aware of the usual motion problems of LCDs. Of course, I wouldn't want to use the technology in a reference monitor. The great advantage of a CRT is that it does very little processing to the signal. If you want to view MPEG artifacts, that's just what you need. Bring in receiver processing, and you have no idea what is causing what artifact.
At NAB, I saw a small OLED being used as a top-mount viewfinder, and it looked good. The OLED is light-emitting like a CRT, rather than the light valve that forms the basis of the LCD. With an OLED, there are no off-axis problems like with an LCD. The OLED has a fast switching time. The early displays had a short life, but current technology promises about 20,000 hours or two-and-a-half years of continuous operation. LCDs are limited by the life of the backlight, so nothing lasts forever. In fact, the CRT receiver I disposed of was only four years old — a very short life compared with the 12 years I got from a Trinitron. The tube was OK, but the EHT was playing up, and it's more expensive to get something fixed than to buy a new one.
Of course, the CRT had its problems. Because the EHT regulation was poor, you had to overscan to avoid seeing that the picture size was modulated by the inverse of brightness. That was just a cost-saving issue. My CRT computer monitor was very stable as to geometry. Both CRTs had convergence errors at the corners, but that's to be expected in an analog system.
Do I mourn the passing of the CRT? Yes. I look forward to the day when a technology like OLED means we can move from the LCD. I don't believe that a light valve using polarized light is ever going to be anything but a compromise. They are great for laptop displays of business graphics, but full-motion video needs accurate gray-scale tracking, deep blacks and better motion reproduction. The LCD has advantages. It's much lighter than a CRT, takes up less room on my desk, and the geometry is fixed by the grid of the display. And as for plasma, space doesn't permit any comments, but I have seen very good pictures on large displays.
By the way, I do watch the programs in addition to the artifacts.
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