Way to block out light for non-contact calibration?(of Plasmas) - AVS Forum
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post #1 of 3 Old 01-31-2013, 03:11 PM - Thread Starter
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So, I've come across many mentions that it's inadvisable to use contact-mode for plasmas especially with colorimeters, even the D3 Pro, which I will be using. Mounting it on a tripod is straightforward, it's just ensuring that ambient light(from PC monitor) doesn't interfere that's a problem. I haven't been able to find something that's intended to enclose and extend the 'range' of the meter so that it's field of view is close to the screen. I thought about just getting some posterboard, or using one of these but the thought occurs to me that the color/reflective material in such things could alter the light seen by the meter. Is this a valid concern or am I overthinking things?

I'm also hoping that perhaps someone here has a better solution they could share.
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post #2 of 3 Old 02-01-2013, 10:30 AM
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If the room is otherwise dark except for the PC monitor, just make sure the PC monitor is well back from the meter so light given-off by the PC monitor is not directed at the meter... distance and reflections will diminish the monitor light enough that it shouldn't be an issue for a flat panel calibration.

You can also turn down the PC monitor's brightness if needed, or even cover the monitor while making readings... much easier than trying to block light from the meter and TV. You really don't want to "cover" a plasma... they emit quite a bit of heat from the vent holes in the back AND from the screen in the front... you want enough open space around the TV for that heat to escape without being trapped.

You need to understand the viewing angle of the meter you are using, You want to calibrate plasma TVs with window patterns and you want the viewing area of the meter to fall inside the window patterns you are measuring so the meter isn't "seeing" a lot of black around the window pattern... you only want the meter to "see" light coming from the window pattern. The viewing angle of colorimeters is all over the map so you can't make any assumptions about how close or how far the meter should be from the screen... you have to KNOW you are at the right distance. For some meters, that could be 6" and for others it could be 3 feet or more.

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post #3 of 3 Old 02-01-2013, 10:52 PM - Thread Starter
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Quote:
Originally Posted by Doug Blackburn View Post

If the room is otherwise dark except for the PC monitor, just make sure the PC monitor is well back from the meter so light given-off by the PC monitor is not directed at the meter... distance and reflections will diminish the monitor light enough that it shouldn't be an issue for a flat panel calibration.

You can also turn down the PC monitor's brightness if needed, or even cover the monitor while making readings... much easier than trying to block light from the meter and TV. You really don't want to "cover" a plasma... they emit quite a bit of heat from the vent holes in the back AND from the screen in the front... you want enough open space around the TV for that heat to escape without being trapped.

You need to understand the viewing angle of the meter you are using, You want to calibrate plasma TVs with window patterns and you want the viewing area of the meter to fall inside the window patterns you are measuring so the meter isn't "seeing" a lot of black around the window pattern... you only want the meter to "see" light coming from the window pattern. The viewing angle of colorimeters is all over the map so you can't make any assumptions about how close or how far the meter should be from the screen... you have to KNOW you are at the right distance. For some meters, that could be 6" and for others it could be 3 feet or more.

I was also considering that option. I just had thought, well, I'd heard of some calibrators claiming even the reflection of small LEDs, such as those used to indicate power on/off, would compromise the accuracy of a meter. With the need to use window patterns to calibrate a plasma I was afraid the distances from the meter to the screen would be too far. With APL patterns also being recommended for calibrating plasmas the extra light from the color windows on those patterns seemed likely to bleed into the meters fov regardless so... Well, this has been far more complicated than I thought it would be. Although I'd heard of the different viewing angles meters have I didn't come across any information specific to the D3 Pro yet. Hopefully I can over the weekend, someone might post it here, or google could provide answers.
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