Contrast question - test patterns - AVS Forum
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post #1 of 4 Old 06-06-2012, 12:06 PM - Thread Starter
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On Spears & Munsil and Disney WOW disk there are 2 different types of Contrast tests. One shows the white test pattern bars going from 231 to 254 and the other shows 4 squares of White, Blue, Red and Green.

Right now I am using these tools on a Samsung E7000.

If I start at full contrast (100) I need to lower the setting to 98 to see all of the white bars on the test pattern.

When I get to the Clipping test, the white and green squares show the concentric boxes fine but the red and blue do not. To see the concentric squares in the red and blue boxes I need to turn down the contrast setting to around 83.

My question is which setting is technically correct, or which of the settings should I be using?
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post #2 of 4 Old 06-06-2012, 12:19 PM
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Quote:
Originally Posted by ruiz00tx View Post

On Spears & Munsil and Disney WOW disk there are 2 different types of Contrast tests. One shows the white test pattern bars going from 231 to 254 and the other shows 4 squares of White, Blue, Red and Green.
Right now I am using these tools on a Samsung E7000.
If I start at full contrast (100) I need to lower the setting to 98 to see all of the white bars on the test pattern.
When I get to the Clipping test, the white and green squares show the concentric boxes fine but the red and blue do not. To see the concentric squares in the red and blue boxes I need to turn down the contrast setting to around 83.
My question is which setting is technically correct, or which of the settings should I be using?

83 is the most correct setting.

When one of the RGB boxes start to blend the different levels, that means you are clipping that channel. Correct calibration means letting each channel run all the way up to 254, the only time to compromise on that is if you have very limited light output on a projector (below maybe 7 or 8 fl) or plasma ( below 25fl).

Joel Barsotti
SpectraCal
CalMAN Lead Developer
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post #3 of 4 Old 06-06-2012, 12:23 PM
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Quote:
Originally Posted by ruiz00tx View Post

On Spears & Munsil and Disney WOW disk there are 2 different types of Contrast tests. One shows the white test pattern bars going from 231 to 254 and the other shows 4 squares of White, Blue, Red and Green.
Right now I am using these tools on a Samsung E7000.
If I start at full contrast (100) I need to lower the setting to 98 to see all of the white bars on the test pattern.
When I get to the Clipping test, the white and green squares show the concentric boxes fine but the red and blue do not. To see the concentric squares in the red and blue boxes I need to turn down the contrast setting to around 83.
My question is which setting is technically correct, or which of the settings should I be using?

The S&M patterns are meant to show WTW all the way up to 254, while the Disney WOW patterns are meant to show a tiny bit of WTW, so that 235 appears distinct from higher levels but the high levels might all look alike (relative to one another). How much WTW you want to show (if any) is up to you and keep in mind the more you show, the more contrast ratio you sacrifice for levels 16-235. Technically speaking showing WTW all the way up to 254 is ideal but if you're more concerned with getting the highest contrast ratio from your set, I would follow the Disney WOW patterns instead which only show a little WTW (similar to DVE HD Basics).
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post #4 of 4 Old 06-06-2012, 01:19 PM - Thread Starter
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Thanks for the info guys.
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