"High Definition Benchmark" BD Edition by Stacey Spears and Don Munsil - Page 24

You should see both the two right bars and the checker. One of the checker squares is 16 and the other 17. They might be difficult to see from your chair, if gamma is good, but they are there. Put your nose to the screen to see them.

thanks SS

Stacey - Thanks for the prompt reply.

I meant second from the right. I do see 4 bars and I see the checkerboard.

When I turn down Brightness until only 2 bars are left and the left bar of the 2 is barely visible, the checkerboard disappears. I have to leave the left bar of the 2 pretty bright to see the checkerboards. So yes, I can see the checkerboard when only the left 2 bars are not present, but the leftmost bar of the 2 that remain is clearly visible, not barely visible as the instructions state.

Is it preferable to have the leftmost 2 bars as described in the instructions or to crank Brightness up to see the checkerboard too?

When set correctly you should see the checkerboard and the right two bars.

The reason the 2nd bar from the right it is clearly visible is because the video is coming out of black fast, instead of slow. This is usually a gamma problem. If your display will let you adjust gamma, you can try changing it. If not, you will have to live with it.

It may also be that your brightness control is too coarse. Again, not much you can do in this situation.

As long as you can set so that the checker and two right bars are visible, you are OK.

Thanks much Stacey. I will play around with it more. I don't have tools to properly tweak greyscale.
In any case the DLP picture looks terrific. The blacks are better than I ever thought possible, as I am coming from a CRT-RPTV that had inky blacks & great shadow detail.

I initially used the Contrast and Dynamic Range patterns to set my contrast. In THX mode on my display I set the contrast to 40 (when the brightest bar just barely fades into the background). Then I looked at the Clipping pattern. The advice here was to lower the contrast "just until all the levels are distinct and visible". I ended up lowering it to 35.

Is this the correct approach? Should I be using the Clipping or the other two patterns to fine tune the contrast?

One more thing. 35 (or even 40) seems low compared to what others have their contrast set at (70s or 80s). Should I just trust what the patterns are telling me? What is the down side to a contrast set so low?

When you lower to 35, is it because of the white boxes or the color boxes? The contrast pattern covers the luma channel only. The clipping includes color clipping. We really should have created some color contrast patterns. I personally setup my displays so that neither pattern is clipped.


What are others using to set their contrast control? I would trust the pattern. The downside is that you may end up with a lower contrast ratio overall. Some people strive to push their contrast ratio numbers up as high as possible. Another reason is they may find the TV too dark after setting contrast so low.

I pretty much set the contrast on the Panasonic plasma in the 30s to 40s. I would need to double check.

It is because of the color boxes. The white is fine a little higher.

Stacy,

Will this DLP checkerboard pattern on checking gamma also work for a plasma since it also dithers?

I don't know. On the 3D Panasonic display, there is an odd color in the middle of the checkerboard. I need to correct the grayscale first and see if it goes away.

At the end of the day, the most accurate method to measure grayscale for any display is to read a window pattern at every level and plot it in Excel. Not practical as you need a good a special meter to go that low. I have a Minolta LS-100 that works well. Photoresearch has a more advanced meter, that is 5x more expensive and a lot more accurate down low.

We have finally published our article on how to choose a color space. I hope you find it helpful. http://www.spearsandmunsil.com/artic...olorspace.html

Awesome! Thanks Stacey! Have one on me!
Have a great holiday weekend! You're the man!

Just got done calibrating my Vizio GV47L using the Oppo BD83 and your disc.

Is there any reason to adjust the red, green or blue levels in the TV?

I have seen some posts where people have adjusted these. Is there any tests on the disc where you would touch these settings?

The only one I saw where you might use them is the clipping test. Do you need to see all the boxes from the largest to the smallest in each color or just make sure they are all the same?

They are used to adjust the color temp or gray scale. This is done using a meter and special software, like CalMAN.

Two things:

1) I have read that the overall luminance (or is it illuminance) that you ideally want on a Plasma display is between 30 and 40 ftl. If I set the Contrast and Brightness settings properly according to your disc, I come out with 26 ftl at 100 IRE. If I want to get near or past 30 I need will end up clipping whites and primaries by raising the Contrast. What do you recommend? Clipping to get into the 30-40 range or sticking with the settings I arrived at after using your test patterns?

2) Is sharpness dealt with differently in Plasmas compared to LCDs? Most have recommended that my Sharpness be 0 or at most 10 on my plasma. LCD recommendations seem to be to raise it until you notice artifacts. One article said that most set it at about 1/3 to max. Do plasmas and LCDs handle Sharpness differently?

Stick with the settings; the overall luminance of the screen is not a huge issue, within a reasonable range. The standard for movie theaters used to be around 16 foot-lamberts, and you can get a pleasing picture even at much lower luminance, if you have decent light control, so you've got plenty of light.


The way plasmas handle sharpness digitally is essentially the same (though of course there are no clear standards for how the sharpness control is implemented, so each manufacturer may be doing slightly different things), but the perception of sharpness may be different because of the differences in the way the panels display. But those differences should settle out, because sharpness has to be set perceptually, and is affected by your seating location, overall light level, and size of display, among other things.

Our recommendation is to sit at your normal viewing location with the sharpness pattern displayed, and turn up the Sharpness control until you can see artifacts like jagged diagonals or curves, or noticeable halos near edges. Then back the Sharpness off until these artifacts disappear.

I would add that the light output for broadcast monitors was speced at 30fl. This is for a 20-30" display. The larger the display, the less fl it will produce. Even at 30fl, the 30" BVM can't meet the spec w/o blooming. Some post houses would set to 30 and others would set to the point of blooming. I think the 30" would start to bloom around 23fl.

So by using the numbers by someone who has used one of these programs for my TV should I mess with changing my RGB then re calibrate with your disc or just leave them at factory settings?

I would not use the numbers from someone else. They may or may not work.

I purchased an EyeOne LT meter recently and have used it for a gray scale calibration. The "Gray Scale for Dummies" guide that I was using suggested that I use the meter to set the Color and Hue settings as well. Not surprisingly, they don't trust any filters. In the past, I had calibrated my Color and Hue using the blue filter that came with your BD. It seemed to work very well. Interestingly, when I calibrated the Color with the EyeOne meter, I had to lower it from 50 to 47; not a huge difference, but when I looked at a color pattern through the filter again it was noticably off.

BTW, the meter and the filter perfectly agreed for my Hue setting.

So, what should I trust? The setting I got with the filter (I even tripled up the blue filter to maximize its effectiveness) or the setting I got with the meter? Which is more accurate?

Hard to say. What are you measuring when you are setting color and tint with the EyeOne LT? The Color Bars pattern on our disc, another disc, or something else?

I used a HCFR 100% color window (on the AVCHD disc since you don't have those patterns) and set the Color by adjusting the luminance of a primary as a percent of the luminance of 100% white. The guide said the red luminance should be 21% of the white luminance. Since setting Color effects all primaries equally, setting Color with the Red window should be consistent for blue and green as well. I did similar calculations for blue (8%) and green (71%) to check for consistency and it was at most off by one Color step.

Broadly speaking a colorimeter is a more accurate way to set color in many situations than using a filter. For example, the method outlined in that guide will work reasonably well even if your display uses a CMS to adjust the effective primaries, whereas using a filter will often not work well if the display has a CMS.

However, even without a CMS you could have inaccuracy in setting the color with the EyeOne via:

- Small mismatches between the EyeOne filters and theoretically perfect XYZ filters.
- Red push in the color decoder (which would make red brighter than the other two channels, which would cause you to turn color down to compensate).
- Light reflected off colored surfaces in the room (though typically this is a tiny factor; you'd need to have some large bright-colored object to shift the reading noticeably).
- Roundoff in the calculations in that guide. (Red should be 21.26% of white, green should be 71.52% of white, and blue should be 7.22%)

With the filter, you can have inaccuracy via:

- Red push
- Leakage from the other two channels
- CMS

So bottom line there are too many intangibles to say. The filter is a direct method that is essentially the same method used by video engineers for years, and on a normal TV with no red push or CMS, and with no visible leakage from the green and red channels, it's extremely accurate. But from everything I've heard the EyeOne is plenty accurate enough to set color correctly.

Are you confident that your TV has no CMS? And can you see the other colors turning absolutely black on the color bars pattern? If so, then the filter seems pretty solid to me.

If, on the other hand, you're not confident about whether your TV has a CMS (or you still see faint ghosts of the other colors through the filter), and you re-check the numbers from the EyeOne with the coefficients mentioned above (and definitely measure all three primaries, not just red), I think using those settings is a perfectly reasonable approach. Unless you want to invest in a pro calibration with a spectroradiometer, I don't think this is a question that can be completely answered via forum posts.

Broadcast monitors have almost always had a blue-only mode, so they don't need to use filters.

Thank you for you informative feedback, gentlemen. I appreciate it.

I am positive that my Panasonic does not have CMS. I can only adjust the gray scale. Regarding the blue filter. It is (seems) quite good. Looking through the 2x shows a bit of leakage of the red and green. The 3x is very dark, and there may be a slight leak, but it is hard to tell. (The 1x shows very obvious leakage.)

The EyeOne LT seems to work well. One thing I have noticed is that when I am taking a continuous reading that the values will fluctuate. The luminance usually drifts downward after a couple of minutes, so it makes my calculations a bit variable. I suppose I should wait until it bottoms out. My only thought there is that the plasma does have some image retention and I wonder if having the 100 IRE White on screen for 5 minutes will effect the readings of the primaries (due to IR). Any thoughts on how to best handle this luminance "drift"? Is this typical of meters or just my entry level one?

Yeah -- that's the "essentially" part of the phrase "essentially the same method."

Maybe we should say that it's a decent alternative to using a blue-only mode for TVs that don't have one.

BluCheez, I that luminance drift can be the TV warming up, the EyeOne warming up, random fluctuations, or maybe sunspot activity or gremlins. I'd say the first one is most likely. Plasma TVs actually literally warm up, so in general you want to take measurements after they've reached operating temp. So turn on the TV, let it run with normal material on it for 15 minutes or so, then put up the window pattern and measure immediately. At least that's what I'd do.

If you put up a window pattern, measure, and then 5 minutes later measure again and it's changed, but then if you show a black screen for 5 minutes, then the window, and it's back to the original measurement, then I'd guess you're seeing some kind of short-term phosphor fatigue. You could use the first measurement or the average of the high and low. I wouldn't really use the measurement you get after the pattern has been up for a long time; that's not a good simulation of normal viewing.

Thanks. I do make sure I let the display warm up for at least 30 minutes with the EyeOne on it. It could be gremlins... I need to check under the couch. Phosphor fatigue makes the most sense. I'll make sure I take my readings sooner rather than later.

Flucation occurs on all displays. You can measure five times and get five slightly different results. On my DLP the change occurs in the 3rd digit. e.g. .001, .002, etc...

Hi guy's,

I love your disc.

I own every Video Essential discs (3 different ones) and your
disc is now my go to disc.

I just have a question with regards to Y’CbCr 4:4:4, 0-255. Does it change the gamma settings for a projector?

I will tell you my equipment.

I use the Oppo BD-83 (I also have a Denon DVD 3930CI and PS3 slim) that goes to a Denon AVR 3808 that goes to a Cineversum Blackwing 3 (based on but tweaked JVC RS2).

Oppo is set on Y’CbCr 4:4:4.
Denon i/p scaler is off. It reports Y’CbCr 4:4:4 12 bit in and out.
Cineversum Blackwing 3 is set to HDMI Enhanced. Gamma setting 2.4 (I read somewhere that was recommended).

Once the projector was set to Enhanced it showed the below black and above white info. I had to adjust down the brightness and raise up contrast.

I used your disc to calibrate and it has done an awsome job. Black bar 17 shows, but no others. White 253 shows and no clipping of the colours.

I was happy untill someone mentioned that DVD and Blu is only in Y’CbCr 4:2:0 8 bit 15-235 and that I should calibrate to that. I was told if I don't all my Gamma would be out of wack.

Is this correct? or have I done the right thing calibrating the way your disc recommends?

I didn't notice any Gamma issues. It looks the same to me. The picture has an excellent dynamic range now.

Thanks

Ta

Dono

Both DVD and Blu-ray are 8-bit 4:2:0 with a range from 1-254. Reference black is at 16 and reference white is at 235, with values above and below. When the OPPO is set to YCbCr 4:4:4, this is what you get. Have you read the Color Space article yet to ensure 4:4:4 is the best choice?

Bottom line, Your calibration is OK.