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I use to work at night and it is eye-hurting to watch at lightbulb-bright screens (I've got two - laptop's built-in panel and an external 18-inch CRT) in a dark environment. So I adjust my screens to be darker.

Can I do this a software way instead of pressing monitors' buttons that many times every time?

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up vote 19 down vote accepted

I have been using this. Its very nice.

sudo add-apt-repository ppa:jonls/redshift-ppa  
sudo apt-get update && sudo apt-get install redshift gtk-redshift

gtk-redshift is just the gui, not required.

f.lux is also an option.

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No need for ppas any longer. Redshift is included in natty. Just do sudo aptitude install redshift or sudo aptitude install gtk-redshift (the latter for the gtk variant which comes with an icon for the tray). – N.N. Jun 14 '11 at 11:56
I cannot use Redshift for manually correcting gamma – Anwar Shah Aug 20 '15 at 5:58

The software you're looking for is Redshift redshift

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Thank you, this thing is great. – mrSuperEvening May 6 '12 at 22:50

You can always do Windows-M or Windows-N. The first inverts colors of all windows showing, the second does it to the current window in focus.

Really helps when reading PDFs with tired eyes

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To those who have problem with brightness configuration after installing Ubuntu 10.10 and are using Acer Aspire 4741, here's a solution for you:

gksu gedit /etc/default/grub

Change the line GRUB_CMDLINE_LINUX="" into GRUB_CMDLINE_LINUX="acpi_osi=Linux"

sudo update-grub

Restart your linux

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To adjust gamma (which is a good substitute for adjusting contrast), you can write:

xgamma -gamma 0.3

on the command line (Terminal). You should see a very noticeable difference. Experiment with different values.

1.0 is the normal (uncorrected) gamma value. Setting a lower gamma (for example 0.7) will increase the contrast of bright luminances, which makes midtones darker and decreases white washing. Setting a higher gamma (for example 1.5) will make midtones brighter and increase the contrast of dark luminances, but also increases white washing.

For my inexpensive laptop, I use gamma 0.8 to compensate for the too bright factory setting for the LCD and I find that the gamma correction helps with color reproduction too, which is nice because so far I haven't managed to get any color calibration working on this LCD.

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