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Manual SDR Calibration of JVC X7900 projector using Colourspace ZRO.

 
Author Helipilot
ZRO
Male
#1 | Posted: 20 Jan 2021 22:02 
Before calibration I prepared a series of patch lists.
To perform Greyscale calibration I created a 14 step greyscale set of patches.
To perform Colour calibration I created 5 step saturation sweeps for Primaries and Secondaries.
To evaluate my completed calibration I created a combined 10 step greyscale and 5 step saturation sweeps.

To get the most accurate manual calibration I use a custom gamma curve on the projector. This allows me to have 14 point gamma control via the autocal software. The JVC user menu only has two point control as standard.

Greyscale Calibration

I started by warming up the projector. I then loaded JVC Autocal software.

Autocal Home page

I chose the gamma option and loaded in the custom gamma curve I wanted to use and applied a gamma preset as a starting point (in this case 2.4).

Autocal gamma page

I then loaded up the ColourSpace ZRO software.
In the settings page, I set patch/scale resolution (16-235). I also ticked the auto box in the Profile Luma section.
On the Manual Measures page, I loaded in my 14 point grey scale patch set.
On the Manual Measure page I used the test patterns to set brightness and contrast
Greyscale Calibration
I measured black (0,0,0) and then white (255,255,255).
I then measured 80 % (204,204,204) I used this patch to set gain controls on the projector.
I then measured 30% (76,76,76) I used this patch to set offset controls on the projector.
I then ran an auto advance measure through the full patch set.
I then used the Autocal software to refine the gamma response to reduce any "Y" error.
I performed continuous measurements on the patch that I was adjusting
A little bit of effort revisiting each step got the greyscale adjusted with deltaE errors under 2.

ZRO RGB balance

ZRO greyscale deltaE

Colour Calibration
On the Manual Measures page, I loaded in my Colour sweep patch set.
The JVC only has basic colour management so I decided to use 75% saturation patches to calibrate the primaries and secondaries. The reasoning behind this is to ensure the majority of viewing material is as accurate as possible with the limited controls available.
I then ran an auto advance measure of all patches to look at the overall colour accuracy on the CIE diagram.

ZRO colourCIE

Over time I will use my evaluation patch set to check how well the calibration settings are holding as the lamp ages.
Not the best set of results I have ever seen, but a reasonable starting point considering its the first time I have used the software.
Now I need to try an HDR calibration.

I have attached my patch sets so that any JVC projector owners may use them.

https://www.lightillusion.com/forums/shared_files/storage/Misc/jvctx7900tpatchilistsdam.zip

Author Grabthars Hammer
ZRO
Male
#2 | Posted: 24 Jul 2021 11:13 
Thanks for posting this tutorial. I have two questions:

- Which patterns size do you have used?
- Why are you setting the Software to legal/ limited range pattern (16-235) and then using "wrong" 80 and 30% pattern?

Author Helipilot
ZRO
Male
#3 | Posted: 24 Jul 2021 18:02 
Grabthars Hammer:
- Which patterns size do you have used?

I created a patch window that covered about a sixth of the screen. This allowed me to align the probe and still see the majority of the screen to choose the appropriate patterns.

Grabthars Hammer:
- Why are you setting the Software to legal/ limited range pattern (16-235) and then using "wrong" 80 and 30% pattern?

The 80% and 30% patterns refer to my preset list. The ZRO software automatically converts to the correct patch values depending on the patch/scale settings you have chosen, so 80% (204,204,204) generates a 191,191,191 patch.

Author ConnecTED
LTE
#4 | Posted: 24 Jul 2021 20:03 
Hi Helipilot,

About your calibration procedure, you can start your calibration by performing 100% White calibration using the RGB Gain controls.

Keep one channel untouched and reduce values from the other two channels.

While you are doing that, adjust your peak output using IRIS adjustments.

It will not require adjusting the RGB-Bias; it's not recommended. (its effecting low end in a wrong way)

After your 100% White calibration, start the JVC AutoCAL using the Quality setting (to perform 33-point AutoCAL).

After the AutoCAL, take verification measurements to see the AutoCAL results.

You can improve further using the RGB-Gain again (if required) or use the 12-Point gamma controls.

The screenshots of your ColourSpace have the wrong black level (min Y), and you have a very low peak (max Y).

Its looks like as a level mismatch problem of your patterns generation / software settings / JVC HDMI input.

Consumer players (media/network/blu-ray/streamers) are using video levels, so your calibration should be performed for LEGAL patchscale.

LEGAL patch scale will require using LEGAL patchlists (16-235), like Ted's patchlists.

The patchlists you have uploaded are in full range (0-255).

Author ConnecTED
LTE
#5 | Posted: 24 Jul 2021 20:10 
Helipilot
Helipilot:
The 80% and 30% patterns refer to my preset list. The ZRO software automatically converts to the correct patch values depending on the patch/scale settings you have chosen, so 80% (204,204,204) generates a 191,191,191 patch.

Hi,

ColourSpace will generate the exact value you see to the software to your generator, and it will not scale anymore.

We were using full range patchlists, and ColourSpace was scaling according to patchscale setting only in older ColourSpaceZRO versions (4-5 months ago).

The current version needs a LEGAL patchlist for LEGAL patchscale or FULL patchlist for FULL path scale.

If ColourSpace sees a mismatch, it will highlight the problematic patch.

I have posted pictures here: https://www.lightillusion.com/forums/display-calibration-8/colourspace-zro-recommended-settings-as-starting-point-812.html

Author Helipilot
ZRO
Male
#6 | Posted: 24 Jul 2021 20:41 
Thanks for your insight Ted.

I posted this guide way back in January, hence the 0-255 range for my patch lists and ZRO making the appropriate conversion. I no longer use the ZRO software to generate the patches as I have purchased HTL software to go with my Lumagen Pro and now use the Lumagen as a pattern generator to create LUTs for my calibrations.

Regards

Alan

Author ConnecTED
LTE
#7 | Posted: 24 Jul 2021 21:38 
Hi Alan,

Ops, I had missed that... to see when this thread was created, I thought it was new.

But for new users of ColourSpace/ColourSpaceZRO, can use the OMARDRIS method with JVC AutoCAL:

https://www.lightillusion.com/forums/msg.php?id=4852

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 Manual SDR Calibration of JVC X7900 projector using Colourspace ZRO.

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