My laptop configuration is Dell Inspiron 1440. I want to reduce my laptop screen brightness in Ubuntu below the minimum level that can be set using system settings. I usually set my screen brightness to an ultra low level, as it hurts my eyes.

I have already searched for the solution online and found related posts:

The problem is that in my case the screen brightness value in the file /sys/class/backlight/acpi_video0/brightness is already 0.

I have tried installing backlight and setting it to 0, and overwriting the value again as described in one of the posts above. However, none of it helps. I am currently using the latest version of Ubuntu 13.10. Thanks,

  • I had already gone through the instructions given in the post mentioned above. It does not solve my issue. – qstack Jan 3 '14 at 10:43
  • Yes, I know, but that doesn’t mean there is any point to re-asking a question. Unfortunately you are still too new here, so you don’t have enough reputation points to post a comment at the other question. I’ll flag this so that a moderator can convert it to a comment to the other question for you and hopefully someone can find an answer for both of you. – Synetech Jan 3 '14 at 15:22
  • @Synetech It's not usually a problem to ask a new question when you've tried everything mentioned in the possible duplicate, but it still doesn't solve your problem. Questions now are closed as duplicates in order to point people to an answer. If the answer didn't work for them, there's no point in closing it. (This has changed a little over the last months. See When a user posts a duplicate but adds “none of the answers there worked”, is it a duplicate?) – slhck Jan 4 '14 at 19:43
  • There’s also no point in re-posting it if it couldn’t be solved already. Just bump the previous question. – Synetech Jan 4 '14 at 23:52
  • acpi_video0 would not work for me, the one that fine controls brightness in on intel_backlight. I have changed boot parameters for the system to use only this one, and forgets about acpi_video0. – pepper_chico Jan 28 '14 at 11:52

Reduce the brightness by changing the value in the following file:

sudo nano /sys/class/backlight/intel_backlight/brightness

Set the value to 0 for absolute low brightness.


You can try "f.lux". With it, you can change how the colors are displayed on your screen and maybe your eyes like the new way. That program will try to simulate a low light level ambient in your screen.


  • 4
    That’s not what f.lux is for; it only adjusts the color temperature of the screen, which is not what is being asked here. – Synetech Jan 3 '14 at 5:01
  • f.lux is not supported for ubuntu 13.10 . – qstack Jan 3 '14 at 10:47
  • 1
    Which is neither here nor there because it’s not what you’re looking for anyway. You need to adjust the gamma/contrast/brightness levels. – Synetech Jan 4 '14 at 23:52

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