Newbie question about 20 Point IRE - AVS Forum
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post #1 of 5 Old 08-20-2013, 06:40 PM - Thread Starter
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Hello, I've been playing around with my TVs options for the past few days now and I've had some things come up that I'm confused about. It'd be greatly appreciated if someone could help me understand. The TV is a 42" LG PJ550.

I don't own any color measuring equipment or anything (though I am beginning to consider looking into this), but I've been messing around with the AVS HD 709 calibration disc, as well as trying some settings that have been suggested online (I realize these won't necessarily be a good fit for my TV in my living area, but I figured I'd try them and see how I liked it).

So anyways, my biggest confusion right now is why I don't see any difference at all when I adjust the numbers in the 20 Point IRE setting. Newbie as I am, I would have no idea how to set up the 20 Point IRE myself, even if I had the proper equipment, but a couple of the suggestions online did include settings for 20 Point IRE so I tried them out. I just went through each IRE level (5, 10, 15...) setting the Red, Green, and Blue to what was suggested. As I was going through I couldn't see any difference, so I tried using the Expert 2 setting and replicated all my settings except I left the 20 Point IRE stuff all at default 0's. I tried flipping back and forth between the two and I could not see any difference at all. I'm using a PS3 plugged into HDMI and playing games by the way, if that makes a difference. I think I am just not understanding how this works or maybe I'm confused about what it should actually be doing.

Oh, one more thing! I had tried a configuration suggested in the PJ550 official thread (the settings were for a different TV but the person that posted them said the PJ550 was a similar set and they seemed to really like the results they got from the settings) but for me, it just turned everything very very blue. Does anyone have any idea why that is (I don't think my TV has a blue filter, or at least I can't find it if it does)? It goes blue once I set this part of the settings:

Color Temperature: Warm
Method: 2 Points [see below]
Pattern: Outer
Red Contrast: -18
Green Contrast: 0
Blue Contrast: -10
Red Brightness: -17
Green Brightness: -22
Blue Brightness: 25

Color management system [no adjustment]

Looking at them it kind of seems natural that it would turn everything blue to me, since everything else is put into the negatives while blue is turned up to +25, but I really wouldn't know.

Thank you for your time.
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post #2 of 5 Old 08-21-2013, 03:19 PM
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Here's an image showing what you're messing with: http://digitalfilmfarmworkshops.com/content/wp-content/uploads/2012/10/Gray-Scale-0-100.jpg

You can see that 20 IRE (which I believe is actually a misnomer - it should be 20%) is a step on the grayscale (the scale from black to white). It sounds like you have 20-point controls on your TV meaning that you can fine-tune at a pretty granular level, at 5%, 10%, 15% and so on. However, first you'd adjust more roughly using 2 point controls: the low or darker end (RGB brightness/cuts/offsets controls) and the high or whiter end (RGB contrast/gains).

A pretty good and simple explanation of the goal is at http://www.curtpalme.com/forum/viewtopic.php?t=10457. Simply read the "What is greyscale calibration?" and "Why should I do greyscale & colour calibration?" sections.

You can't do any of this without a meter though. If you don't have a meter, leave the grayscale/white balance controls at default and use a disc to set your basics: Contrast, Brightness, Sharpness, Color, and Tint.

There's a lot of good info in the stickies if you want to know more: http://www.avsforum.com/t/1283669/links-to-this-forums-popular-threads

Edit: you're already using a disc smile.gif Also, I'm a DIY calibrator myself and I'm very, very pleased with my investment in an entry level meter + software. A properly calibrated grayscale makes a huge difference on PQ and it's been a fun learning process.

Adjusting settings according to personal preference is not calibration.
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post #3 of 5 Old 08-21-2013, 05:15 PM
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As Willie mentioned, there's no such thing as IRE in digital video. IRE is an analog video concept that has no place in digital video, though some software companies and video equipment manufacturers don't seem to realize that it's wrong to keep using it in the digital video domain. In digital video we use % white (like 5%, 10%, 15% etc.) or digital levels 16 for black, 235 for 100% white, etc.

And I agree with Willie, there's nothing you can do with the CMS controls or gain/bias/offset contriols without a meter and software.

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post #4 of 5 Old 08-21-2013, 05:45 PM - Thread Starter
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Thank you for the replies guys!

The article you linked, willieconway, was indeed very easy for me to understand. Now I actually have an idea what the 2-point vs 20-point settings actually do.

Still, even knowing that the settings I grabbed off the internet to try adjusting each 5% point on the grey scale are likely incorrect for my TV, they are still different from having each 5% point adjusted by 0/0/0. Despite being different I wasn't able to notice a difference in my picture switching back and forth between a preset that had them set all to 0's vs the setting that set them all to *something*. From the article it sounds like if my grey scale was out of whack (which I suppose it would be, putting in settings without a meter) even my colors should've been off, so I would've expected to see the colors change. Perhaps the difference was small enough that my eyes didn't catch it, or maybe I was looking for some large change and missing the small changes.

I'm definitely interested in buying an entry level meter and software as well, since I wasn't completely satisfied with just the disc. Trying to get my set to look right is becoming somewhat of an obsession. I'm starting to do some research on the entry level options, and I suspect I'll be back to this forum in the next few days to pick everyone's brains wink.gif.

Thanks again for the help and explanations you guys. I'm starting to get very interested in this topic and love learning more about it.
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post #5 of 5 Old 08-23-2013, 01:29 PM
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Display a 50% white Window/field from avs709 disc and play with level 10. On my lg I can defenitely see colored grays but if you cant see changes maybe flawed controls.

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