GCD - Gamut Calibration Disk - Page 5

I think a simpler menu would be better, the menu switching is fast enough that it's not painful anymore.

Top menu

-10% Windows
-25% APL
-Color Checker

10% Windows menu
-Saturation Sweeps
-Luminance Sweeps
-Primaries/Secondaries

Same for APL

Backround is nice, maybe add a picture like this to the top menu.

Beautiful
And pattern fields!

Yes! For Front Projectors.
My LED Samsung UE55B7000 bad calibrate windows
good calibrate APL and fields (saturation because they are not in APL in AVCHD).

Best regards,Andrei.

Need pattern 80% saturation - best calibration- 50% volume of a cube - minimum mistake!

75% isn't good enough for you?

80% mathematically exact - cubic root of 0.5 - 0.7937 - 79.37% pattern about 80%!

Given all the other uncertainties in the calibration process, 75% is fine.

Now understood, thanx!

as you read about gamma:
http://www.brucelindbloom.com/index....dCalcHelp.html

If you go to the trouble of mathematically finding the "best" gamma, you will find that its value depends on your definition of "best."

If best means minimizing the largest error, then the best gamma is 2.1723.
If best means minimizing the RMS (root mean square) error, then the best gamma is 2.3243.

That example answers the question "What value for gamma gives a companding function that most closely represents the CIE L* function (i.e. a uniform perceptual scale)?"

Unfortunately, this definition is not used as a reference in video production.

I understand

Why 1% APL patterns?
Where 25% APL?

Thank you!

Where 10% Windows with 25% APL?
I find only 1% Windows with 25% APL.

Why use 10% patterns not recommended THX for plasma?

10% size windows inside of 25% background do not have constant APL

For gamma=2.2, 120 cd/m^2 white
10% windows: APL(10%)=4.8 cd/m^2, APL(100%)=9.9 cd/m^2
1% windows: APL(10%)=4.4 cd/m^2, APL(100%)=4.8 cd/m^2



@visca

I used the disk this morning to do a 75/75 (w/windows) calibration and it worked very nicely! Clipping pattern is nice too. There are still menu navigation problems though:

1. Whenever I hit top menu button it goes to windowed luminance sweeps
2. There is no way within sweeps to go up 1 level, can this be assigned to the return button?

The grayscale ramps are important because all of the color work at saturation <100% depend on gamma, so having those in windowed and APL will be needed.

thanks!

Did not know.
Now I know.
Thanx.

What patterns calibrate my TV LED Samsung UE55B7000?

Greyscale pattern?

Thanks for fixing the top menu button. Greyscale patterns work fine and the 25% APL is a good place to work for plasmas with "gamma lift", I can easily measure the contrast enhancement in the 10,20, and 30% levels. One small nitpick - the 5% steps icon is oversized in both menus.

 

Red=1% on 25% grey background

Blue=10% windows

Edited by zoyd - 6/10/12 at 5:44pm

Beatyfull!

Here is a new version of the target spreadsheet which includes the bt.1886 gamma checker. It also now auto calculates the targets for arbitrary average gamma.

 

GCD_targets v4.xlsx.zip 91.470703125k . file

Super!

Visca Blaugrana and Zoyd!
This disk only gamma 2.2 or it can be used for different gamma?

Any gamma - use the spreadsheet to calc targets

Checked out color patterns and they look good, will be doing some comparisons between full saturation and 75%, 50% calibrations using the color checker patterns to grade the result. I think the spreadsheet is complete as well, this version includes targets for user measured gamma of arbitrary shape.

 

GCD_targets v5.xlsx.zip 114.8798828125k . file