Almost all LCD owners will notice some degree of clouding effect on their HDTVs during dark or completely black scenes. What is the clouding effect? It’s a varying degree of brightness visible across the screen. HDTV reviewers tend to describe the clouding effect as “poor screen uniformity.” It can be caused by different sources, most often from uneven backlighting or flaws in the LCD’s matrix of thin-film transistors. Clouding is most noticeable when a single dark color is shown on the screen, eg, black or dark blue. Other terms for the effect are backlight bleed, flashlight effect, cloud effect, and mura or the mura effect. Mura is a Japanese word meaning an unevenness, blemish, or inconsistency. The clouding effect is generally limited to LCDs because plasmas have a different back light technology.

One way to combat this effect is to avoid watching your television in completely dark rooms. Turn on a lamp with a low light setting to keep a small amount of ambient light in the room. Some LCD manufacters offer ambient light built in to their television, most notably Philips Ambilight.

Review site Secrets of Home Theater and High Fidelity just posted an excellent review of the GV47LF. The reviewer used Datacolor Colorfacts professional calibrating equipment to calibrate the television. So any owners of the GV47LF should head on over there and check out the entire the review for tips on getting the best picture from the television. I can say their suggesting settings improved my viewing experience.

Their suggested calibrated settings for the Vizio GV47LF:

• Red: 133
• Green: 126
• Blue: 106

Their suggested advanced picture adjust settings for the GV47LF:

• DNR: Off
• Black Level Extender: On
• White Peak Limiter: On
• CTI: Off
• Flesh Tone: On
• Dynamic Backlight: AI
• Adaptive Luma: On

I’ve been messing around with the backlighting settings on the television, and I’ve come to the conclusion that leaving the dynamic backlight setting on AI is the best way to go, whether you’re in a well-lit room or in a dark room. I’ve found that turning off dynamic backlighting in the advanced settings and adjusting the manual backlight to a low setting (less than 40) tends to make dark scenes murky, and can turn a bright sunny scene into an overcast day. If you use the above settings and dynamic backlight on AI, you’ll get the best compromise of black levels and vivid colors that this TV has to offer. You’ll also have more peace of mind by not having to fiddle with the television anymore, knowing the settings are from a professional calibration.

*Update* I’ve been using these settings for months now, and I am still totally happy with the picture in all lighting settings. I have not touched the settings nor plan on touching them any time in the future. Again, I recommend viewing your Vizio GV47LF in dimly lit rooms–avoid total darkness.

*Update II* Please note that picture settings for each input (broadcast TV, component, HDMI, etc) must be changed while in that mode–they do not replicate across all inputs. See my post on the subject.

*Update III* My GV47LF developerd a buzz sound (out of warranty, of course) that was produced from having the dynamic backlight set to AI. I have now changed it to On (this solves the buzzing problem while maintaining the bright, vivid picture the dynamic backlight provides). I have also messed around with the other picture settings and find that reducing the brightness to 47-50 and having contrast cranked up to 90-100 helps increase the black levels.