[Tips] Screen Color Calibration for the Galaxy Nexus

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After using the Galaxy Nexus for two weeks, I found the screen color of the new amoled+ is much better than the Nexus S, but still inaccuracy. I'm a part-time photographer who keen on the right Gamma, color accuracy and color temperature.

So I just finished some test with such things:

1. Galaxy Nexus
2. franco Kernel 18.5 nightly(with the ColorControl from Ezekeel)
3. Voodoo Screen Test app
4. x-rite i1 Display 2 color meter
5. HCFR software

The test result was not so good...

• Average Gammar value is about 1.9, far from the ISO stand 2.2. So the color is just too bright (I'm not saying screen brightness).
• The shadow part (0-40% gray level) of 3 color curve were almost out of trim. In another words, incaauracy color balance.
• As the color unbalance. The color temperature is starting from lower than 5500K to 6500K, which the ISO stand is 6500K at any color level.

I also tested the ColorControl in franco Kernel. After the adjustments, Gammar value is still bad, but I save the (most part of) color balance & color temperature in the end.

The adjustments step by step:

1. Make sure you have a rom/mod with /init.d autorun function.
   
   Bye, stock rom...:P
   
   
2. Make sure you have a kernel with ColorControl function.
   
   Such like Ezekeel, franco...Else? I don't know.
   
   
3. Set the screen brightness to 50%.
   
   It's the mesurement "baseline". But why 50%?
   Because, at this point the screen has a brightness about 120 Lux--also a ISO stand. So, it's very close to our desktop LCD.
   
   
4. Make a new file as /etc/init.d/900colorcontrol-b50
   
   Which could be done by Root Explorer or adb.
   
   Inside the file, type such line:
   

   echo "-10 0 -10" > /sys/class/misc/colorcontrol/v1_offset
   
   echo "1820000000 1900000000 2000000000" > /sys/class/misc/colorcontrol/multiplier

   I choose "182 190 200" here, because the default value was about 200. Rising will increase the risk of LED Burn-in.
   
   And, don't forget the 7 zero!!!
   
   
5. Just reboot & enjoy the almost right color temperature.
   
   It's (6500±300)K at any color level in my device. Not perfect, but much better indeed.
   

Done, that's all I can do for you.

Thanks so much for the mod.

I'm willing to test your new calibration for the GNex color but how can I revert back to stock in case of problem ?

So I guess we can only use this modification at 50% of brightness ? If we change to auto, how could it be ?

Sorry for being a noob here, but this is compatible with any rom/kernel right? I'm currently running on AOKP Build 25 and Popcorn kernel 7.1

Thanks,
Mosh

Hi, and thank you for offering your expertise. I'm not confident in doing the above.... Can you offer a little bit more step by step?

I've played around with root explorer which I imagine is what is necessary to change these values.you lost me at the 2nd step.....

Also, is 50% necessary?

Thanks kindly,



_______________________________
frAncO Kernel ;-P

Originally Posted by mazubo

Hi, and thank you for offering your expertise. I'm not confident in doing the above.... Can you offer a little bit more step by step?

I've played around with root explorer which I imagine is what is necessary to change these values.you lost me at the 2nd step.....

Also, is 50% necessary?

Thanks kindly,



_______________________________
frAncO Kernel ;-P

Originally Posted by mohitrocks

Sorry for being a noob here, but this is compatible with any rom/kernel right? I'm currently running on AOKP Build 25 and Popcorn kernel 7.1

Thanks,
Mosh

Originally Posted by heo_con184

Thanks so much for the mod.

I'm willing to test your new calibration for the GNex color but how can I revert back to stock in case of problem ?

So I guess we can only use this modification at 50% of brightness ? If we change to auto, how could it be ?

Step by step detail added. Thx for reading~

Thanks for the guide!

Sent from my Galaxy Nexus using XDA App

You can change all of these settings from Franco's kernel updater program directly without modifying any files.
The OP's settings appear a little warm at first but I'm liking them so far...

Sent from my Galaxy Nexus using xda premium

Can you please add this file 900colorcontrol-b50

sooooo do i make a folder in system like this?

system/etc/init.d/900colorcontrol-b50 and then add that text above or??

Instead of making that script, can we just input those numbers into the Color Control?

-10, 0, -10 for Gamma (RGB);
182, 190, 200 for Multiplier (RGB)

Right?