Brightness Control Program

[Doretta Castoe]

Iam looking to add controls to adjust screen brightness locally in my app menu but can't seem to figure out how to do it. I have seen examples to max-out or dim brightness but I am looking to add controls so that the user can control and set the brightness level. Does anyone have any examples, tutorials, source code, or just a place to point me in the right direction?

The documentation calls that setting from 0 to 255. I am trying to figure out whether it shuts the screen off at 0, as at one point I had a widget installed with a slider and you'd cause the screen to shut off if you set it to 0.

Dimmer is a small and free application for Windows, designed to help you adjust the brightness of your computer screen, monitor or display. This becomes very useful when you are in near or total darkness and the minimum brightness from your display or screen is still too much. Dimmer offers a fast and easy way to correct this, so you can adjust the brightness of your displays. It can dim all your screens and monitors; LCD, TFT and LED backlit types (even old CRTs). It supports multiple screens, displays and monitors with convenient individual controls to adjust each one.

Always wondered how to reduce your screen brightness? Or, how to dim your computer monitor, screen or display? Wonder no more. Dimmer was created for this exact task, to help you lower the computer screen brightness, so you can work with no detriment to your eyes.

By reducing the brightness of your screens, Dimmer helps to protect you from excessive light radiation which damages your eyes. It has helped to save the eyesight of thousands of people since 2007. Some say it's better than carrots. Dimmer is designed to run on all versions of Windows in a quick, easy and intuitive way. It's also very lightweight on system resources, ideal for everyday use.

Donate Support this project Did you find this application useful? If so, please consider giving back a small contribution. Your donation will be processed with PayPal so it's safe and easy. You don't need to have a paypal account in order to make a donation.

The need for this program came about when working at night with minimum ambient light in the room. This was uncomfortable and damaging to the eyes. So one day (back in 2004) I decided to develop Dimmer to solve this problem. The monitor brightness can now be easily adjusted via a slider and/or text input controls which are very easy to use. I eventually released it to the public in 2007.

Another convenient feature is that Dimmer does not require installation. It's a portable application. Simply extract into a folder and run. The program stores its settings into a file in the program folder (for your convenience) so the Windows Registry is not used. When no longer needed, just delete the program folder. When Dimmer runs, it will remember and dim the brightness to the level it was last used.

Dimmer has been much acclaimed over the years for its simplicity and as the best dimming software for displays, screens or monitors. Feel free to recommend it to your friends and family and you may link to this page if you wish. Hope you enjoy and find this software useful.

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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.

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.

First and most importantly, if at all possible adjust the display backlight, rather than using software correction of pixel values. If you dim the backlight you still get full or near-full dynamic range, giving you a clearer, "deeper" image that tends to be more readable.

Software adjustment can't make the blacks darker, it just makes white greyer and reduces contrast. So instead of using pixel values from 0-255 it might use from 0-180 for example. Everything looks flatter.

Last I checked, most displays unfortunately do(did?) not implement backlight control from software. There's a standard for it, DDC/CI but adoption has been limited. Try the ddccontrol tool with your monitor and see if you have any luck.

I've only seen it in very high end displays intended for calibrated photo and video work ... and even many of those use a USB connection and custom USB HID based driver instead of the DDC/CI standard. I'm pretty outdated though, and the linked article claims that basic options like brightness and contrast are widely supported now.

Some cheap displays don't support backlight control at all. The brightness controls on the display just adjust the pixel values on the LCD, just like software control does. Do not use these controls if you have such a monitor; it's usually better to do the correction in software, certainly no worse.

All too many displays do have backlight control, but minimum brightness is still eye-searing. They can sometimes be modified, but otherwise your best bet is setting them to minimum backlight brightness and then living with changing pixel values to get them even dimmer.

It really annoys me that displays have such a limited backlight intensity range, often artifically and arbitrarily limited, starting at eye-searing to "the power of a million suns". I look for dim backlights when I'm speccing out displays to buy.

The details are somewhat driver and software specific, but your laptop should offer convenient Fn keys that make it easy, and the OS should have a simple display brightness slider. The xbacklight utility offers a convenient command line control for this, though on my system it doesn't seem to like to go below 1% brightness and goes straight to black.

I twiddle the driver controls because my T460 is very bright - wonderful during the day, but horrible at night. The minimum brightness step offered by the fn key adjustments is still way too bright, but the driver provides much finer grained control. xbacklight only lets me get down to brighness 8/255 and I'd like So I tell it to run at 4/255 brightness:

When you lower brightness you might want to increase contrast in software a bit, especially if working on text. It'll cost you image quality, but gain you readability at low brightness. The xgamma utility will let you do that, e.g.

Will set gamma to the default value (1 for each color channel). Select the appropriate output by choosing from one of the connected devices, listed with just xrandr (or xrandr grep -vE "^ " grep -v disconnect).

--gamma red:green:blue Set the specified floating-point values as gamma correction on the crtc currently attached to this output. Note that you cannot get two different values for cloned outputs (i.e.: which share the same crtc) and that switching an output to another crtc doesn't change the crtc gamma corrections at all.

--brightness brightness Multiply the gamma values on the crtc currently attached to the output to specified floating value. Useful for overly bright or overly dim outputs.

Note: his is a software only modification, if your hardware has support to actually change the brightness see this answer.

The title of your question suggests you are looking for a generic tool to adjust brightness/contrast and gamma of your desktop. The body of your question suggests you are looking for automatic adjustment matching the time of day. I was looking for an answer to the first variant and found only xcalib, a command-line utility. Thus I have written a gui front-end for xcalib, which can be found on

Well, I just wanted this yes/no simple question to Dell e-mail support. Their web site required service code just to send an e-mail. Then I tried their "technical" chat support. Some Indian person responded weirdly and finally answered that he/she did not have technical knowledge and just gave me the link to the e-mail support (which I tried already).

DDC/CI (Command Interface) standard was introduced in August 1998. It specifies a means for a computer to send commands to the monitor, as well as receive sensor data from the monitor, over a bidirectional link. Specific commands to control monitors are defined in a separate Monitor Control Command Set (MCCS) standard version 1.0, released in September 1998. DDC/CI monitors are sometimes supplied with an external color sensor to allow automatic calibration of the monitor's color balance. Some tilting DDC/CI monitors support an auto-pivot function, where a rotation sensor in the monitor enables the operating system to keep the display upright as the monitor is moved between its portrait and landscape positions. Most DDC/CI monitors support only a small subset of MCCS commands and some have undocumented commands. Many manufacturers did not pay attention to DDC/CI in the past, but now almost all monitors support such general MCCS commands as brightness and contrast management.

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