Database Users

[Q] What are Gamma settings?

What exactly does gamma do?
I read somewhere that you can tweak gamma settings with no effect on battery life. So you can turn the screen brightness to the minimum and raise a color setting to make the screen contrast better.
It seems to be a popular feature in kernels, but what exactly do people aim to achieve by changing their gamma settings, I don't get it...

quoting myself from another thread:
dagaetch said:
2.2 is the value you want. As for why, see http://www.cambridgeincolour.com/tutorials/gamma-correction.htm; basically, electronic images are biased a certain way, and gamma correction is intended to remove that bias. since screens are different, you need different settings to correct the appropriate amount to reach 2.2, which apparently became the industry standard at some point.
Click to expand...
Click to collapse

It seems to be a popular feature in kernels, but what exactly do people aim to achieve by changing their gamma settings, I don't get it...
Click to expand...
Click to collapse
we aim at making our eyes happy

dagaetch said:
quoting myself from another thread:
Click to expand...
Click to collapse
Thank You! I think that pretty much halfway answers my question.
Now I wonder the effects of gamma settings on battery, and what brightness/gamma configuration is more 'eye pleasing'.
Is there a general consensious on what that configuration miht be on the Nexus 4 or will I have to play with settings to find out my own?

mastrgamr said:
Thank You! I think that pretty much halfway answers my question.
Now I wonder the effects of gamma settings on battery, and what brightness/gamma configuration is more 'eye pleasing'.
Is there a general consensious on what that configuration miht be on the Nexus 4 or will I have to play with settings to find out my own?
Click to expand...
Click to collapse
There's a few presets that you can find on xda but in reality they'll all need tweaked a bit. Like the other guy said, every screens different.
Nexus 4
ATT Straight Talk $45/mo
running xylon 2.1 4.2.2 faux kernel

mastrgamr said:
Now I wonder the effects of gamma settings on battery, and what brightness/gamma configuration is more 'eye pleasing'.
Click to expand...
Click to collapse
No effect on the battery. This phone has an LCD screen with a backlight, so no matter the colours, the battery drain is the same. The only possible side effect is of your gamma tuning leaves your screen so dark that you have to bump the brightness, which could affect the battery.
Sent from my Nexus 4

[Q] Color calibration?

Hi!
I've noticed that my screen has (okay) color.
I've also noticed that it is possible to calibrate them.
I've tried this through franco.kernel updater and YES, the color has improved.
Now, which calibration settings and procedure would you recommend for the best results?
A different kernel or app perhaps? Specific color profiles, maybe?
Thanks!

Franco has an app in the Play store for our devices. Nexus 4 Display Control

bg1906 said:
Franco has an app in the Play store for our devices. Nexus 4 Display Control
Click to expand...
Click to collapse
The options here are identical to those offered by his kernel updater app.
I want to know which color settings profiles offer the best results.
Which ones do you use?

arvindch said:
the options here are identical to those offered by his kernel updater app.
I want to know which color settings profiles offer the best results.
Which ones do you use?
Click to expand...
Click to collapse
238
228
240

bg1906 said:
238
228
240
Click to expand...
Click to collapse
Those are RGB values, right?
And, gamma settings?
Thanks!

arvindch said:
Those are RGB values, right?
And, gamma settings?
Thanks!
Click to expand...
Click to collapse
RGB
Gamma can't be modified on the stock kernel which is what I run. However, Franco allows you to adjust gamma with a custom kernel, however I don't know the settings.

bg1906 said:
RGB
Gamma can't be modified on the stock kernel which is what I run. However, Franco allows you to adjust gamma with a custom kernel, however I don't know the settings.
Click to expand...
Click to collapse
Yeah, I'm running franco's kernel + prima drivers.
Thanks for the RGB values. I'll try them out.
Also, anyone running franco.kernel is welcome to post their preferred RGB+gamma values.
Thanks!

The Franco kernel app comes with a big set of gamma profiles submitted by users. You need to press a button in the app to be able to see those though.
I suggest trying those to see if there's something you like.
Sent from my Nexus 4

steviewevie said:
The Franco kernel app comes with a big set of gamma profiles submitted by users. You need to press a button in the app to be able to see those though.
I suggest trying those to see if there's something you like.
Sent from my Nexus 4
Click to expand...
Click to collapse
Yeah, I tried a few of those. But, it's hard to compare the differences.

[Free APP] Nexus 5 gamma reverse engineering App. Please contribute!

Nexus 5 Gamma Reverse Engineering App is out!
(This app will work on the common sysfs interface, so any kernel using this interface will be compatible with this app, not just my kernel)
Please download my public betas here:
http://faux.androidro.ms/hammerhead/beta/
Franco Kernel is also compatible here:
http://forum.xda-developers.com/showthread.php?t=2508284
ALL Gamma registers are accessible with new APK!
@myfluxi Thank you again!
After hitting apply, it's best to turn screen on/off to see the results updated!
Please help decipher the meaning of these values and write them down in a concise manner so we can all understand what you've done and tried.
My TODO list for this FREE app:
Once things are figured out, I will add:
1: "Set On Boot" options to automatically apply the new values on startup (right now "set on boot" can be dangerous and lead to black screens).
2: Perhaps some basic profiles
3: Maybe other cool stuff if time permits
Min Value is 0 (NO NEGATIVES)
Max Value is 255 (Don't Go over it, it will break stuff!!!)
App Change Log:
1.0.6 - Initial release with RGB register access only
1.0.7 - full access to all registers
1.0.8 - add "set on boot" feature, add webview link to 2nd post below, enabled landscape mode.
1.0.9 - updated to latest kernel driver. add old version warning. add action bar for quicker navigation.
1.0.10 - updated to latest kernel driver. removed unused fragments.
1.0.11 - updated to latest kernel driver with stable sysfs locations!

Progress So Far:
Gamma Tabs:
columns => goes from left to right, so 1st position is most let and right most is 5th position
row => goes from top to bottom.
I got VERY CLOSE to ideal Gamma 2.2
Positive and Negative Polarity tweak added. This allows for greater RGB gamma control and balance!
Overall Color Gamma Curve (row 1 column 1 of RGB Gamma tabs) => 0 is highest, 255 lowest
Red Gamma Positive=> 0
Green Gamma Positive=> 73
Blue Gamma Positive=> 78
Red Gamma Negative => 0
Green Gamma Negative => 73
Blue Gamma Negative => 78
Gamma Color Brightness (row 2 column 5 of RGB Gamma tabs) => 0 is highest, 255 lowest
Red Gamma Positive => 100
Green Gamma Positive => 117
Blue Gamma Positive => 121
Red Gamma Negative => 107
Green Gamma Negative => 117
Blue Gamma Negative => 121
Overall White Point Brightness => 0 darkest, 255 brightest
Gamma white point, Column 1 => 30

reserved for answers2

reserved for answers 3

You know there is a section for apps right?
http://forum.xda-developers.com/google-nexus-5/themes-apps

brooksyx said:
You know there is a section for apps right?
http://forum.xda-developers.com/google-nexus-5/themes-apps
Click to expand...
Click to collapse
this is to help reverse engineer the kernel drivers. it is relevant in this section for kernel development.

faux123 said:
this is to help reverse engineer the kernel drivers. it is relevant in this section for kernel development.
Click to expand...
Click to collapse
Guess that makes sense.

So I guess if I don't know what this means I should just leave it alone?

uh60james said:
So I guess if I don't know what this means I should just leave it alone?
Click to expand...
Click to collapse
yeah. this is for the advanced users or tinkerers who like do not mind tweaking their phones. If you are not comfortable with this, you shouldn't participate.

faux123 said:
yeah. this is for the advanced users or tinkerers who like do not mind tweaking their phones. If you are not comfortable with this, you shouldn't participate.
Click to expand...
Click to collapse
Already broke my phone. hahah. Gamma 31 is evil. =D
Thanks Faux, I've been aching to play around with these settings since I got my N5.
***Edit*** Oh my God! YELLOW TINT IS GONE!!! *faints*

Thanks for this faux Great stuff

another gr8 from faux
thanks

karendar said:
Already broke my phone. hahah. Gamma 31 is evil. =D
Thanks Faux, I've been aching to play around with these settings since I got my N5.
***Edit*** Oh my God! YELLOW TINT IS GONE!!! *faints*
Click to expand...
Click to collapse
What settings did you use?

BDHela said:
What settings did you use?
Click to expand...
Click to collapse
Play with green gamma settings by lowering all settings by 6-10 points
Gamma 1 to 255/25/33/33/33
Gamma 3 to 10/33/33
Gamma 5 to 0/32/32
Gamma 20 to 200/33/6/0/6
Gamma 22 to 200/33/33
Don't remember if I modified Gamma 28
Gamma 31 to 200/70/60/55/55
I didn't touch blue gamma or red gamma much, modifying values to see effect now.

faux123 said:
Nexus 5 Gamma Reverse Engineering App is out!
(This app will work on the common sysfs interface, so any kernel using this interface will be compatible with this app, not just my kernel)
Please download my public beta 04 here:
http://faux.androidro.ms/hammerhead/beta/
ALL Gamma registers are accessible with new APK!
@myfluxi Thank you again!
After hitting apply, it's best to turn screen on/off to see the results updated!
Please help decipher the meaning of these values and write them down in a concise manner so we can all understand what you've done and tried.
My TODO list for this FREE app:
Once things are figured out, I will add:
1: "Set On Boot" options to automatically apply the new values on startup (right now "set on boot" can be dangerous and lead to black screens).
2: Perhaps some basic profiles
3: Maybe other cool stuff if time permits
Min Value is 0 (NO NEGATIVES)
Max Value is 255 (Don't Go over it, it will break stuff!!!)
Click to expand...
Click to collapse
What does mean "it will break stuff "?
Thanks
Inviato dal mio Nexus 5 utilizzando Tapatalk

Polv89 said:
What does mean "it will break stuff "?
Thanks
Inviato dal mio Nexus 5 utilizzando Tapatalk
Click to expand...
Click to collapse
Well black screen or messed up screen. .. Things not working. .. I don't know what more to say. ..
Sent from my SM-N900T using Tapatalk

Polv89 said:
What does mean "it will break stuff "?
Thanks
Inviato dal mio Nexus 5 utilizzando Tapatalk
Click to expand...
Click to collapse
I think an explanation that this won't brick your phone but just require a wipe to fix a messed up screen world be useful to allay some fears. A flashable zip to restore to stock would be wonderful too. I'm gonna experiment nonetheless but others might need some reassuring.
Edit: meant for faux. Dang xda app causes me to quote the wrong person.
Sent from my SCH-I605 using xda app-developers app

karendar said:
Play with green gamma settings by lowering all settings by 6-10 points
Gamma 1 to 255/25/33/33/33
Gamma 3 to 10/33/33
Gamma 5 to 0/32/32
Gamma 20 to 200/33/6/0/6
Gamma 22 to 200/33/33
Don't remember if I modified Gamma 28
Gamma 31 to 200/70/60/55/55
I didn't touch blue gamma or red gamma much, modifying values to see effect now.
Click to expand...
Click to collapse
a screen shot?
i am a bit confused

Great news!
Ideal Gamma 2.2 Achieved!
:highfive::victory:
2nd post updated!

With both karendar's and faux's settings my screen has much more contrast, beautiful colors, but is also less bright. Recommend it anyway !
Sent from my Omniromed and Faux kerneled Nexus 5 using Tapatalk

Gpad screen gamma is too low

Some of you may have noticed it's difficult to watch dark scenes in movies on the gpad. I think the problem is the gamma calibration, you can see it clearly on the pictures I took.
https://imageshack.com/i/nf96iaj
On the top you can see my nexus 7 2013, you can differentiate all the shades of grey from 1% white to 100%.
On the gpad, everything is solid black from 1% to 12% of white.
You can find the original image here : http://imageshack.us/f/594/6291.png/
How low can you go, on your gpad, before the grey melts with the black ?
Do you know an app to apply gamma correction ?
Here you can see the same picture on the N7 and the gpad. You can't even distinguish the guy's ear on the g pad.
https://imageshack.com/i/f563trj

bobo69 said:
Some of you may have noticed it's difficult to watch dark scenes in movies on the gpad. I think the problem is the gamma calibration, you can see it clearly on the pictures I took.
https://imageshack.com/i/nf96iaj
On the top you can see my nexus 7 2013, you can differentiate all the shades of grey from 1% white to 100%.
On the gpad, everything is solid black from 1% to 12% of white.
You can find the original image here : http://imageshack.us/f/594/6291.png/
How low can you go, on your gpad, before the grey melts with the black ?
Do you know an app to apply gamma correction ?
Here you can see the same picture on the N7 and the gpad. You can't even distinguish the guy's ear on the g pad.
https://imageshack.com/i/f563trj
Click to expand...
Click to collapse
I see the difference, and I knew it was there already also.. I'm sorry, but apparently gamma is not something that is doable. - I was looking to link you the app from market called "Screen Adjuster", however you want to look at this description, especially the last sentence. ;/
- dimming the screen 15-100% (below minimum system brightness)
- screen color and a contrast adjustment
- system brightness 0-100% adjustment
- functional widget (on/off, system brightness, settings)
- autorun option
Some phones have a color tint screen. This app have a possibility to try to improve colors on this kind of the screen by setting an additional factor RGB.*
The range of the dimmer is from 15% to 100% (it allows to dim the screen below a min system brightness value). Make a relief for your eyes during a nightly reading.
Furthermore, you can change fast the system brightness too.
The additional contrast factor can try to make the reading or a picture viewing more comfortable on some screens.*
The widget provides fast on/off service with a shortcuts to the Adjuster settings and the system brightness settings.
The application has the autorun option which works with the dimmer set above 22% (for the safety).
Note
A gamma adjustment is not possible to do.
You can of course try and download the app anyways and see if contrast or brightness will do anything for ya.
- In case you do download the app, remember that setting contrast low will result in problems with installing apps, as in you cannot hit Install, only cancel. To avoid this, open up Screen Adjuster and turn it off, install the app and turn it back on afterwards. It's something about lowering the settings to lower than what is "intended", I don't quite understand it and I find it rather odd. But it let's you install apps.. So I guess hooray.
That's all I got.

CuraeL said:
I see the difference, and I knew it was there already also.. I'm sorry, but apparently gamma is not something that is doable. - I was looking to link you the app from market called "Screen Adjuster", however you want to look at this description, especially the last sentence. ;/
That's all I got.
Click to expand...
Click to collapse
Thank you for your response, but I'm already using screen adjuster. I set the contrast at -25 and it helps a lot to see dark details.
Unfortunately, it has two side effects :
- it brightens the dark shades of grey, but also the black levels.
- I noticed that the contrast setting also affects the white making it look like light grey.
So the contrast setting in screen adjuster doesn't affects only the dark tones like it would on a monitor or a tv, it affects the contrast ratio.
I've found apps to make gamma adustment but it only works on some devices with custom kernel.
https://play.google.com/store/apps/details?id=com.teamkang.fauxclock&hl=fr
- Gamma curve (Galaxy Nexus, Nexus 4, HTC One, Nexus 7 2013)

bobo69 said:
Thank you for your response, but I'm already using screen adjuster. I set the contrast at -25 and it helps a lot to see dark details.
Unfortunately, it has two side effects :
- it brightens the dark shades of grey, but also the black levels.
- I noticed that the contrast setting also affects the white making it look like light grey.
So the contrast setting in screen adjuster doesn't affects only the dark tones like it would on a monitor or a tv, it affects the contrast ratio.
I've found apps to make gamma adustment but it only works on some devices with custom kernel.
https://play.google.com/store/apps/details?id=com.teamkang.fauxclock&hl=fr
- Gamma curve (Galaxy Nexus, Nexus 4, HTC One, Nexus 7 2013)
Click to expand...
Click to collapse
Yea, I was about to say that gamma can be done but only on custom kernels. Lot of Nexus 5 stuff on the market. Apparently it's Google who locked the gamma settings completely down but only in 4.4.2. I guess it may work on stock LG Kernel since it's only 4.2.2? I'm afraid we'll have to wait for some kernel support for other roms. That would be awesome. I really hope for some Franco-kernel-glory on this device.

That's what I thought, we need to wait for custom kernels...I hope it will come soon, because it's so frustrating to have such a good screen with bad calibration !
People tends to complain too much about the warm white balance but the gamma calibration is far more concerning.

bobo69 said:
That's what I thought, we need to wait for custom kernels...I hope it will come soon, because it's so frustrating to have such a good screen with bad calibration !
People tends to complain too much about the warm white balance but the gamma calibration is far more concerning.
Click to expand...
Click to collapse
I hope @dalingrin can cook something up to address both. He said he was going to work on something.

joshuadjohnson22 said:
I hope @dalingrin can cook something up to address both. He said he was going to work on something.
Click to expand...
Click to collapse
Yes it would be great if he did , though he's done so much for us already.
Sent from my LG-V500 using XDA Premium 4 mobile app

I see someone had developed a nude kernel for our devices. I welder off they can add support for gamma adjustment
Sent from my LG-V500 using Tapatalk

I am pleased to say my new kernel BOB Kernel v2 has had the gamma corrected

My first post ever
YoungBobbie said:
I am pleased to say my new kernel BOB Kernel v2 has had the gamma corrected
Click to expand...
Click to collapse
Hi there Young Bobbie, I am new to posting on XDA so I couldn't post this in your kernel developer page. This is my first post on any forum page ever. First off, thank you very much for your hard work to make this kernel happen to correct gamma on the v500. I have been sitting on the fence whether to get the gpad, and if i would get the v500 or the v510. Was leaning toward the v510 because of Sleekmason's wonderful kernel work, but it's exciting that we have now have the same options available for the v500. I noticed this was working fully with the Malladus ROM. My question to you was whether or not this worked with stock LG ROM as well? Thank you again YoungBobbie and Sleekmason for your time and creations.
Sorry, just answered my own question. Guess it helps to read the very first line of the page (making fun of myself now ;-P) Thank you again YoungBobbie and sleekmason!!!

themorningwolf said:
Hi there Young Bobbie, I am new to posting on XDA so I couldn't post this in your kernel developer page. This is my first post on any forum page ever. First off, thank you very much for your hard work to make this kernel happen to correct gamma on the v500. I have been sitting on the fence whether to get the gpad, and if i would get the v500 or the v510. Was leaning toward the v510 because of Sleekmason's wonderful kernel work, but it's exciting that we have now have the same options available for the v500. I noticed this was working fully with the Malladus ROM. My question to you was whether or not this worked with stock LG ROM as well? Thank you again YoungBobbie and Sleekmason for your time and creations.
Sorry, just answered my own question. Guess it helps to read the very first line of the page (making fun of myself now ;-P) Thank you again YoungBobbie and sleekmason!!!
Click to expand...
Click to collapse
Gald to have helped would you be willing to try the kernel for the stock LG ROM?

Please take a look at the images below and compare
The tablet on the right is running my kernel and the left stock
You can see the differences on the first image as the deepness of the blacks
and on the second the highlights on the white

I just about to get this tablet, then i so this problem... ?
Sent from Note 3 Superphone!

Bob2702 said:
Gald to have helped would you be willing to try the kernel for the stock LG ROM?
Click to expand...
Click to collapse
Be happy to. Have to acquire the device first, which will be in a matter of a week or 2

KCAL Colour Calibration

Has anyone played with KCAL values to tweak their display settings?
Edit//
For those wondering here's my setup, you must be on an AOSP rom:
ROM: AICP latest nightly
Kernel: Furnace kernel
Tools: KCAL Color Control & Whetstone
Values for deeper blues/blacks and more of an AMOLED feel:
R:245
G:245
B:256
S:50
V:128
C:128
Also from Superuser_, for those who do not have the SVC options
Superuser_ said:
I don't know if the panels are different,but the following numbers give me brilliant white(cold)
R 216
G 222
B 256
Click to expand...
Click to collapse

Here are my settings.

i actually have something pretty similar as well, looks more like AMOLED after the changes:
R:245
G:245
B:256
S:50
V:128
C:128

I don't know if the panels are different,but the following numbers give me brilliant white(cold)
R 216
G 222
B 256

OK I give, can someone point me to the KCAL setting? I'm only aware of the accessibility/color adjustment.

Same here please. I google KCAL and all I get is apps to do with calorie counting. Is it an app and does the phone need to be rooted?
Thanks

Trickstermod can do the same and is in play store. Need root as kcal too

Here guys: http://downloads.codefi.re/savoca/kcal

imapfsr said:
Same here please. I google KCAL and all I get is apps to do with calorie counting. Is it an app and does the phone need to be rooted?
Thanks
Click to expand...
Click to collapse
rzracer2 said:
OK I give, can someone point me to the KCAL setting? I'm only aware of the accessibility/color adjustment.
Click to expand...
Click to collapse
It seems to be aosp only with a supported kernel

Superuser_ said:
I don't know if the panels are different,but the following numbers give me brilliant white(cold)
R 216
G 222
B 256
Click to expand...
Click to collapse
what kernel are you using?
i was on 777 for a while but it lacked (vs. furnace) the saturation, contrast and value section, those parts seemed to be the most important for getting that deeper/cooler look

Cow07 said:
what kernel are you using?
i was on 777 for a while but it lacked (vs. furnace) the saturation, contrast and value section, those parts seemed to be the most important for getting that deeper/cooler look
Click to expand...
Click to collapse
Yah agree..
I'm on crash rom official..I think has stock kernel
This app let me using only the RGB parameters but with those numbers I have the same white and same level of max brightness compared with my girlfriend's G2

@goxi87 @Cow07 so which Rom are you using? Really wan to know which Rom has the compatible kernel for this app Thanks in advance
"Make it COUNT"

CM12 with Furnace kernel

I installed V1.1 - I am on stock Rom Sprint LS990 and i have RGB settings but no SVC.
Anyone know why???

Must be on Furnace kernel. But this kernel is for AOSP roms.

Thanks! Will definitly switch to furnace
"Make it COUNT"

HK-AD said:
Thanks! Will definitly switch to furnace
"Make it COUNT"
Click to expand...
Click to collapse
I'm on aicp with furnace. 777 has kcal implemented as well but doesn't have the saturation settings though.

HK-AD said:
@goxi87 @Cow07 so which Rom are you using? Really wan to know which Rom has the compatible kernel for this app Thanks in advance
"Make it COUNT"
Click to expand...
Click to collapse
ingoljosh said:
I installed V1.1 - I am on stock Rom Sprint LS990 and i have RGB settings but no SVC.
Anyone know why???
Click to expand...
Click to collapse
I edited my first post to summarize the required things for colour control

Superuser_ said:
I don't know if the panels are different,but the following numbers give me brilliant white(cold)
R 216
G 222
B 256
Click to expand...
Click to collapse
This is working nicely on mine as i am on stock kernel (linux) and only have access to RGB
BIG difference, stock settings gives off a yellowish white (compared to my G2) and with this setting it matches whites exactly. i wish it were a bit brighter though.

ingoljosh said:
This is working nicely on mine as i am on stock kernel (linux) and only have access to RGB
BIG difference, stock settings gives off a yellowish white (compared to my G2) and with this setting it matches whites exactly. i wish it were a bit brighter though.
Click to expand...
Click to collapse
try and the following numbers(if the previous shows to you a bit blue..):
R 229
G 216
B 256