# Application to set monitor brightness based on time of day? **URL:** \ **Category:** Factual Questions\ **Created:** [September 23, 2012, 8:38pm UTC](https://boards.straightdope.com/t/application-to-set-monitor-brightness-based-on-time-of-day/635621 "2012-09-23T20:38:16Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [September 23, 2012, 8:38pm UTC](https://boards.straightdope.com/t/application-to-set-monitor-brightness-based-on-time-of-day/635621/1 "2012-09-23T20:38:16Z")
I have one of those old-school desktop computers without a built-in light sensor, and the monitor controls aren’t very accessible. During the day it’s too dark and at night it’s too bright. Is there a simple utility that would automatically change the brightness based on time of day (or better yet, sunrise/sunset times)? There’s a similar tool called F.lux, but it only changes color temperature and not brightness. ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [September 23, 2012, 8:45pm UTC](https://boards.straightdope.com/t/application-to-set-monitor-brightness-based-on-time-of-day/635621/2 "2012-09-23T20:45:26Z")
I don’t know what it was called, but just last week one of my coworkers had an app installed on his MacBook that would actually change the color temperature and brightness of the display depending on the hour. So it was not only bright, but cool blue during the day; and dimmer but a warm amber during the night. If you can wait until tomorrow I’ll find out what it was called. ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [September 23, 2012, 9:01pm UTC](https://boards.straightdope.com/t/application-to-set-monitor-brightness-based-on-time-of-day/635621/3 "2012-09-23T21:01:00Z")
Cool, although I hope they have a Windows version (forgot to mention that, sorry). ---
**Author:** ![don\_t\_ask](https://avatars.discourse-cdn.com/v4/letter/d/e68b1a/32.png) [@don\_t\_ask](https://boards.straightdope.com/u/don_t_ask)\ **Post date:** [September 23, 2012, 9:16pm UTC](https://boards.straightdope.com/t/application-to-set-monitor-brightness-based-on-time-of-day/635621/4 "2012-09-23T21:16:03Z")
[f.lux](http://stereopsis.com/flux/) ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [September 23, 2012, 9:26pm UTC](https://boards.straightdope.com/t/application-to-set-monitor-brightness-based-on-time-of-day/635621/5 "2012-09-23T21:26:12Z")
> [@don\_t\_ask](#): > > [f.lux](http://stereopsis.com/flux/) Please see the first post. f.lux only changes color temperature, not brightness. ---
**Author:** ![don\_t\_ask](https://avatars.discourse-cdn.com/v4/letter/d/e68b1a/32.png) [@don\_t\_ask](https://boards.straightdope.com/u/don_t_ask)\ **Post date:** [September 23, 2012, 9:45pm UTC](https://boards.straightdope.com/t/application-to-set-monitor-brightness-based-on-time-of-day/635621/6 "2012-09-23T21:45:04Z")
Sorry wrong one. [Dimmer](http://www.nelsonpires.com/software/dimmer/). Works on mine Windows XP with LG flat screen. Good luck. ---
**Author:** ![don\_t\_ask](https://avatars.discourse-cdn.com/v4/letter/d/e68b1a/32.png) [@don\_t\_ask](https://boards.straightdope.com/u/don_t_ask)\ **Post date:** [September 23, 2012, 9:53pm UTC](https://boards.straightdope.com/t/application-to-set-monitor-brightness-based-on-time-of-day/635621/7 "2012-09-23T21:53:47Z")
I should add that when it is run it has to be shutdown before you close windows. ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [September 23, 2012, 10:08pm UTC](https://boards.straightdope.com/t/application-to-set-monitor-brightness-based-on-time-of-day/635621/8 "2012-09-23T22:08:29Z")
> [@don\_t\_ask](#): > > Sorry wrong one. > > [Dimmer](http://www.nelsonpires.com/software/dimmer/). > > Works on mine Windows XP with LG flat screen. Good luck. Thanks for the link, but still not quite ☹ 1. It doesn’t change the brightness, just darkens the image with a layer of black (meaning the backlight is still on full blast) 2. It doesn’t do it automatically based on time of day ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [September 24, 2012, 1:54am UTC](https://boards.straightdope.com/t/application-to-set-monitor-brightness-based-on-time-of-day/635621/9 "2012-09-24T01:54:49Z")
I may have jumped to an assumption in thinking it dims the brightness too. Now I’m thinking he was using f.lux. Either way, I’ll ask him. ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [September 24, 2012, 7:55am UTC](https://boards.straightdope.com/t/application-to-set-monitor-brightness-based-on-time-of-day/635621/10 "2012-09-24T07:55:27Z")
Is there a command in the video signal to change backlight brightness? I thought that’s only controllable on the monitor itself (unless you have a laptop) ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [September 24, 2012, 10:36am UTC](https://boards.straightdope.com/t/application-to-set-monitor-brightness-based-on-time-of-day/635621/11 "2012-09-24T10:36:55Z")
> [@AaronX](#): > > Is there a command in the video signal to change backlight brightness? I thought that’s only controllable on the monitor itself (unless you have a laptop) Yes, through [DDC](https://en.wikipedia.org/wiki/Display_Data_Channel). I’m not sure how many monitors support it, but mine does. On my own monitor I’ve seen software change the brightness and it shows up on the firmware brightness slider too. Here’s a program to demonstrate it: [ScreenBright](http://screenwhite.com/screenbright/). And just to verify it, I have my monitor connected to a watt-meter that shows power usage going up and down with the backlight brightness.