Some of you might have to work at night, or have specific conditions, when he (and many of us) needs a software, that regulates the brightness of screen.  Note, that if you have eye-problems or you are sensitive to screens, then you have to read my another article – Avoid eye-strain with special monitors.

However, if you made a decision to use software, then there is some programs to put screen into “Night Mode” (for PC/laptops: Windows XP,Vista,7, 8,10, etc.. ..). At first, consider what you want to make darker:

At first, you should determine, which things you mostly want to use in a dark environment, for reading or for any purpose. If it is a browser, then we can consider only “browser-addons”.
For example, in Mobile devices (Android, iPhone or etc..), there exists Night Mode for Opera, Night Mode for Firefox and etc.., but if you want to have an app which affects all programs and windows in your PC, then there is needed some other kind of software, which can be installed in Operating System (the below programs are mainly for Microsoft Windows).

1) Night Mode For Windows [mirror]

2) Flux – one of the best utility I have ever seen. It automatically regulates your computer/laptop screen according to your timezone (just you have to set correct timezone in its settings window). Also, you can regulate the amount of luminosity/light…

3) Iris – similar as flux. I have not tested it over a long period, so I cant say how good it could be. You can try yourself and then comment here if it was good for you or not.

4) For browsers, there exists extensions, addons  and plugins. Just search in Google, for example:  NightMode for Chrome (or etc).

5) You can use this flexible  [script]%3Ca%20href%3D%22javascript%3Afunction%20load_script%28src%2Ccallback%29%7Bvar%20s%3Ddocument.createElement%28%27script%27%29%3Bs.src%3Dsrc%3Bs.onload%3Dcallback%3Bdocument.getElementsByTagName%28%27head%27%29%5B0%5D.appendChild%28s%29%3B%7Dfunction%20invertColors%28%29%7Bvar%20colorProperties%3D%5B%27color%27%2C%27background-color%27%5D%3BjQuery%28%27%2a%27%29.each%28function%28%29%7Bvar%20color%3Dnull%3Bfor%28var%20prop%20in%20colorProperties%29%7Bprop%3DcolorProperties%5Bprop%5D%3Bif%28%21jQuery%28this%29.css%28prop%29%29continue%3Bcolor%3Dnew%20RGBColor%28jQuery%28this%29.css%28prop%29%29%3Bif%28color.ok%29%7BjQuery%28this%29.css%28prop%2C%27rgb%28%27%2B%28255-color.r%29%2B%27%2C%27%2B%28255-color.g%29%2B%27%2C%27%2B%28255-color.b%29%2B%27%29%27%29%3B%7Dcolor%3Dnull%3B%7D%7D%29%3B%7Dload_script%28%27%2F%2Fwww.phpied.com%2Ffiles%2Frgbcolor%2Frgbcolor.js%27%2Cfunction%28%29%7Bif%28%21window.jQuery%29load_script%28%27%2F%2Fajax.googleapis.com%2Fajax%2Flibs%2Fjquery%2F1.4.4%2Fjquery.min.js%27%2CinvertColors%29%3Belse%20invertColors%28%29%3B%7D%29%3B%22%3EBookmarklet%3C%2Fa%3E[/script]  (just click on it to see the color-change on screen). If you like that, drag that link into your bookmarks bar (read if you want to know how to enable bookmark bar in your browser) and whenever you want to change colors on particular page, click that Bookmark icon in your toolbar.