Not Too Bright

Dim every screen from the system tray — no more hunting for buttons on the back of the monitor.

Laptops get brightness keys. Desktop monitors get a five-button menu and a Windows that pretends the backlight does not exist. Not Too Bright is a tiny, single-file Windows tray app that fixes that: real backlight control over DDC/CI where the monitor allows it, a laptop's built-in display through Windows' own brightness control, a software dimming fallback everywhere else, and an optional schedule that follows the sun for your location.

Highlights

• Real backlight control - Talks DDC/CI to the monitor, the same channel its own menu uses, so dimming keeps full contrast and saves power
• Laptop screens too - A built-in display is driven through Windows' own brightness control, the one its brightness keys use; changes made with the keys or in Windows show up in the app
• Works on anything - Monitors without DDC/CI (docks, KVMs, virtual displays, remote sessions) get a click-through software overlay instead
• One slider per monitor - Plus All monitors; changes apply live while you drag and are remembered per monitor
• Follows the sun - Optional day/night levels with smooth dawn and dusk transitions computed for your latitude and longitude, shown on an editable graph
• Manual override that makes sense - Touch a scheduled monitor's slider and the schedule pauses until a reset time you choose
• Below the minimum - Optionally continue below 0% on hardware monitors by adding software dimming on top of the lowest backlight setting
• Hide what you do not want touched - Remove a monitor from the app entirely until the next rescan; its original brightness is restored first
• Keep monitors awake - One click in the tray menu keeps the screens on and the computer out of sleep for as long as you choose (2 hours by default)
• Never black, never in screenshots - Software dimming stops at 10% and its overlay is excluded from screen capture and screen sharing
• Zero install - One small executable, no runtime to install, settings in your user registry, nothing written next to the exe
• Self update - Checks this repository for a newer build, shows both version numbers, and replaces itself in place after a standard UAC prompt; automatic checks can be turned off
• Survives everything - Settings follow the monitor (by EDID) and are re-applied after sleep, after displays are switched back on, and after display changes
• Tray icon registration retries while Explorer is starting and recovers automatically after an Explorer restart, preserving the current icon and tooltip; retries stop as soon as registration succeeds

Getting Started

1. Download releases/NotTooBright.exe and run it. An icon appears in the system tray.
2. Double-click the icon. Every connected monitor gets a card with a slider and a badge showing how it is controlled.
3. Drag. That is it - values are remembered per monitor and restored next time.

Hover the icon for a tooltip listing every monitor and its current brightness, headed by a Schedule line (Disabled, Active, or Paused after a manual change), a Keep awake line with the end time while the monitors are kept awake and, while the schedule is enabled, a State line (Daytime, Night, Deep sleep, or the transition in progress, Daytime → Night, Night → Daytime or Night → Deep sleep). Right-click it for Keep monitors awake (see Keep Monitors Awake), Configure and Exit, plus Increase brightness / Decrease brightness and any preset levels you have listed once you have chosen which monitor the menu controls (see Tray menu brightness control), and Resume schedule while a manual change has paused the schedule. Requires Windows 10 or 11 (64-bit) and the WebView2 Runtime, which is already installed on virtually every Windows 10/11 machine.

How Brightness Control Works

For every connected monitor Not Too Bright first tries DDC/CI, the control channel monitors expose over their video cable. It reads and writes the standard VCP brightness code (0x10), so the change is the same one you would make with the monitor's own buttons: the backlight actually gets dimmer, with no loss of contrast. All DDC/CI traffic runs on a background thread with retries, because a single command can take a while and some monitors are slow or flaky. If a driver refuses the raw VCP request but accepts the high-level Monitor Configuration API, that route is used instead.

A laptop's built-in display has no DDC/CI. Windows controls its backlight itself, and Not Too Bright uses that same control (WMI, see Built-in Displays); such a display is recognised and set up before any DDC/CI traffic starts.

When a monitor does not answer (DDC/CI disabled in its on-screen menu, some docks, KVMs, USB-C hubs, DisplayLink adapters, virtual machines, remote sessions), the monitor is switched to software dimming: a topmost, click-through black overlay whose transparency follows the slider. It cannot lower the backlight, but it works everywhere, needs no driver support, and never affects screenshots or screen sharing.

A monitor that has answered DDC/CI before is treated differently when it stops responding (a flaky request after a display change, a KVM switched away, a cable swap): its backlight may well be sitting below 100% from an earlier setting, and dimming it in software on top of that would stack the two. Such a monitor is left exactly as it is, shown as DDC/CI not answering, and retried automatically with a growing delay (3 s, 6 s, ... up to once a minute) until it answers again; its slider applies as soon as it does. Software dimming only remains available as an explicit choice in the meantime. Monitors that have never answered are re-probed a few times after start-up and otherwise use software dimming.

Both methods sit behind the same per-monitor slider. With Allow dimming below the hardware minimum enabled, the slider of a hardware-controlled monitor extends to -90%: values below 0% keep the backlight at its minimum and add software dimming on top, for monitors whose lowest setting is still too bright.

Each monitor is identified by the model and serial number in its EDID, so the chosen brightness is remembered per monitor and re-applied whenever monitors are re-detected: after resuming from sleep, after the displays are switched back on, after resolution or layout changes, and on every start. The first time a monitor is seen its current hardware brightness is adopted as is, so nothing changes until you move the slider, and that original value is recorded for good: hiding the monitor later restores it before the application lets go of the monitor.

Built-in Displays

A laptop's own screen, or any display whose brightness Windows controls itself, shows up with a Hardware (built-in) badge. Not Too Bright sets its brightness through Windows' brightness control (WMI: WmiMonitorBrightness and WmiSetBrightness), the same control the brightness keys, the quick settings slider and Settings use, so the backlight really changes, in the steps the panel supports. Everything else works as for any other monitor: the slider, All monitors, the schedule, the tray menu, Hide (which puts back the level the display had when it was first seen), and dimming below the minimum.

Windows keeps its own ways of changing that brightness, and Not Too Bright follows them as they happen:

• A change you make in Windows - the laptop's brightness keys, the quick settings slider, Settings - shows up on the display's card and in the tray tooltip, is remembered, and counts as a manual change, so it pauses the schedule like moving the slider would.
• When Windows dims the display after a period of inactivity, or switches it off, nothing is written to it; a level the schedule reaches meanwhile is applied once the display is on again.
• Windows applies a level of its own after sleep, when the display comes back on, when you plug in or unplug the charger, and when battery saver turns on or off. The level set in Not Too Bright replaces it a few seconds later.

With debug logging on, everything about built-in displays is logged under [PANEL]: what Windows reports, each change, and how it was taken.

Automatic Brightness

Enable Adjust brightness automatically with the sun in the dialog, enter your latitude and longitude (decimal degrees, north and east positive; a nearby city is close enough), and choose a daytime and a night level. From then on the selected monitors are brightened to the daytime level after sunrise and dimmed to the night level after sunset, every day of the year, using sunrise and sunset times computed for your location and the current date.

Detect from IP fills in the latitude and longitude for you:

• It asks four free services at once (ipapi.co, GeoJS, ipinfo.io, ip-api.com); the first answer wins.
• Each gets 10 seconds. Click the button again to cancel.
• An answer is reused for an hour instead of asking again.
• The result is approximate (usually your provider's city), which is fine for sunrise and sunset.
• Nothing is sent unless you press the button. ip-api.com is plain HTTP and free for non-commercial use only.

If every service is blocked (some DNS filters block them), type the values in by hand.

The graph shows today's curve: the shaded band is daylight, the dashed lines mark sunrise and sunset, and the blue marker is the current moment. The four points shape the transitions - when the morning ramp starts and reaches full brightness, and when the evening ramp starts and reaches the night level. Drag them to taste; they are stored as offsets from sunrise and sunset, so the curve keeps following the seasons instead of freezing at a clock time. When an evening transition overlaps the next morning, the stronger daytime contribution takes precedence so the curve stays continuous across midnight. Reset curve restores the defaults (half an hour on either side of sunrise and sunset). Where the sun does not rise or set on a given day, the night or daytime level simply applies all day.

Deep sleep is optional: at a time of day you choose (23:30 by default) the selected monitors fade over five minutes to a deep sleep level of their own, usually darker than the night level (it can be brighter too), and stay there until the next morning's transition, which then brightens them straight from the deep sleep level. Unlike the four points above, the deep sleep time is a fixed clock time. On the graph, deep sleep shows as a shaded band with a line and a point of its own; drag the point to change the time. Where the sun does not rise, deep sleep lasts until midday.

The schedule is evaluated every 30 seconds and writes to a monitor only when the rounded percentage changes. Solar times are cached for the current date, location, and Windows time-zone settings; clock/settings changes and resume invalidate the cache. Locking the workstation does not stop the schedule. The overlay's 1.5-second check runs only while a dimming overlay is visible, and unchanged schedule ticks do not queue tooltip updates.

The tray icon's tooltip shows where the schedule currently is: State: Daytime or State: Night on the two plateaus, State: Daytime → Night while dusk is dimming the monitors and State: Night → Daytime while dawn is brightening them, State: Night → Deep sleep during the fade and State: Deep sleep after it, and a Schedule line that reads Disabled, Active, or Paused. If you change a scheduled monitor's brightness by hand (its slider, All monitors, or the tray menu), the schedule pauses for every monitor it controls until the cycle reset time you set (04:00 by default), so an adjustment you make in the evening is not undone a minute later; each scheduled card shows Auto paused with a Resume now link, and resuming from any card, from the tray menu's Resume schedule item, or by saving the schedule again resumes the schedule for all of them. Hidden monitors are never scheduled. The night level can only go below 0% when Allow dimming below the hardware minimum is enabled, and each monitor clamps the scheduled value to its own range.

Keyboard Brightness Keys

Many keyboards have Brightness Up and Brightness Down keys. Windows reacts to them by showing its brightness flyout, but only a laptop's built-in panel actually changes; external monitors are ignored. With Use the keyboard's brightness keys enabled, each press moves every listed external monitor by 10% from its own value, whatever window is focused, and counts as a manual change for the schedule. Holding a key repeats on keyboards that send repeated reports. Windows keeps showing its flyout and keeps moving a built-in display itself; Not Too Bright picks that change up (see Built-in Displays).

The keys are not ordinary key codes but usages on the keyboard's HID consumer-control collection, so Not Too Bright opens that collection directly and reads its reports; a keyboard whose brightness keys are handled by the vendor's own software rather than sent as standard HID usages cannot be seen this way. With debug logging on, the [INPUT] lines show which collections were opened and every report they send, which is the first thing to check when a key does nothing.

Keep Monitors Awake

The tray menu's Keep monitors awake for 2 hours item stops the monitors from turning off and Windows from going to sleep on its own, for as long as Keep monitors awake for in the dialog says: 15 minutes to 24 hours, 2 hours by default. While it lasts, the item is ticked and reads Keep monitors awake until 16:42, the tooltip shows Keep awake: until 16:42, and the dialog shows On until 16:42 with Stop now. Choosing the item again, Stop now, or Exit ends it early; once the time is up the monitors and the computer follow the Windows power settings again. Sleep chosen by hand, the power button and closing a laptop's lid still work as usual.

It is a standard Windows power request, so powercfg /requests (from an administrator command prompt) lists it with its end time. The end time is remembered: if Not Too Bright restarts before then, after an update or at the next sign-in, it carries on until that time. A new duration applies the next time the item is chosen. Keeping the computer awake is not a monitor control, so a Remote Desktop session does not pause it.

Remote Desktop

When the session is viewed through Remote Desktop, Windows replaces the real displays with a virtual one, and neither DDC/CI nor a dimming overlay belongs there. Not Too Bright detects this (the SM_REMOTESESSION metric plus the console-session check Microsoft documents for the sessions that metric misses, re-evaluated on every session and display change) and pauses: the monitors keep whatever brightness they have, nothing is probed, written, scheduled, or dimmed, and the overlays leave the remote desktop. The tray tooltip starts with Remote Desktop session: paused, the tray menu's brightness items are greyed out, and the dialog shows the monitors exactly as they were at the computer, with a notice and their controls disabled; the settings can still be changed and saved. A session that was disconnected without signing out counts as remote too. Once the session is back at the console the monitors are re-detected and the stored values are applied again.

Other remote-control tools (VNC, TeamViewer, AnyDesk, Parsec and the like) mirror the console session and are not affected. The behaviour can be turned off with Pause while connected through Remote Desktop for the rare setup where a Windows session is only ever used remotely, for example a virtual machine with an enhanced session, where software dimming of the remote picture is what is wanted.

Updates

When Automatically check for updates is enabled (the default), Not Too Bright checks at startup, whenever the Configure dialog opens, and once every 60 minutes using a single low-frequency Windows timer. A newer build opens Configure and its update prompt; matching or older builds and failed automatic checks are silently discarded. An automatically opened prompt offers Ignore this version, which suppresses that version during later automatic checks, including after restart. The manual Update button still displays every result and can install an ignored version. Checks use the repository's releases/NotTooBright.exe.

The update check downloads the executable to the user's temporary directory and compares its embedded Windows file version with the running executable's version. While downloading, the button displays the current transfer speed rounded to whole kilobytes per second, such as Checking (100kb/s)..., and can be clicked again to stop the check and remove the partial download. The result dialog displays both version numbers. A newer build can be installed normally, while a matching build offers a Force update action to reinstall it; an older repository build is never installed. Installation requests standard Windows UAC approval, safely replaces the current executable, and restarts the application. After a successful update, settings remain closed by default. Select Reopen settings after update in the version confirmation dialog to reopen settings with a confirmation of the newly installed version. Dismissing that confirmation leaves settings open. This checkbox starts unchecked for each confirmation and is not a saved preference; it does not apply to cancelled or failed updates. Cancelling the download, result dialog, or UAC prompt leaves the current version running. File size is used only to validate the download and enforce its safety limit.

Configuration

Double-click the tray icon (or choose Configure from its menu) to open the dialog. It sizes itself to its content, cannot be resized, and has only a Close button. The brightness section applies immediately; the settings below it are saved with Save.

Closing with unsaved settings (Cancel, the Close button, Alt+F4 or Escape) asks Save changes before closing? over a dark overlay. Choose Keep editing, Discard, or Save. Brightness changes that apply immediately are already remembered and do not trigger this prompt.

Control	Description
All monitors	Sets every monitor to the same value (shown only with more than one monitor).
Per-monitor slider	The brightness of that monitor. The badge shows how it is controlled: Hardware (DDC/CI), Hardware (built-in) (Windows' own brightness control of a laptop display), Software (no DDC/CI), Software (chosen), DDC/CI not answering, or Built-in not answering.
Software dimming only	Shown for monitors that have answered DDC/CI or Windows' brightness control. Uses the overlay instead and leaves the monitor's own brightness setting untouched. Useful for monitors that answer DDC/CI but ignore or mangle the values, or that have stopped answering.
Hide	Puts the monitor back to the brightness it had when Not Too Bright first saw it, then removes it from the list and stops controlling it entirely, as if it were not connected: its dimming overlay is removed, it is no longer probed, and no further brightness changes are sent. The last monitor in the list cannot be hidden. Hidden monitors stay hidden across restarts and display changes until you choose Rescan.
Rescan	Re-detects monitors, probes DDC/CI again (for example after enabling DDC/CI in a monitor's menu), and shows every hidden monitor again.
Allow dimming below the hardware minimum	Extends hardware-controlled sliders below 0% into software dimming (down to -90%). Applies immediately. Disabled by default.
Adjust brightness automatically with the sun	Enables the sun-based schedule described in Automatic Brightness. Requires a latitude and longitude. Saved with Save. Disabled by default.
Latitude / Longitude	Your location in decimal degrees (north and east positive), used to compute sunrise and sunset.
Detect from IP	Fills in the latitude and longitude from your IP address; see Automatic Brightness.
Daytime / Night brightness	The levels the schedule applies during the day and at night.
Deep sleep	Optional: a Deep sleep time and Deep sleep brightness. From that time of day the level fades over five minutes to the deep sleep brightness and stays there until the morning transition. Disabled by default; 23:30 and 10% when first turned on.
Today's curve	Graph of the resulting brightness over today; drag the four points to move the dawn and dusk transitions.
Apply to	Which monitors follow the schedule. Newly enabled schedules select every visible monitor.
Cycle reset time	Time of day at which a schedule paused by a manual change takes over again. 04:00 by default.
Tray menu brightness control	Chooses what the tray menu's Increase brightness and Decrease brightness items act on: None (the items are not shown; the default), All monitors, or one specific monitor. Each click moves the target by 10% from its current value; that counts as a manual change for scheduled monitors. Saved with Save.
Preset levels	Shown once a target is chosen: comma-separated brightness levels (whole numbers from 0 to 100, or down to -90 with the extended range on) that appear as their own items between Increase and Decrease, in the order listed. Clicking one sets the target to that level. Anything that is not a valid level is refused. Saved with Save.
Keep monitors awake for	How long the tray menu's Keep monitors awake item keeps the monitors on and Windows out of sleep each time it is chosen: 15 minutes to 24 hours, 2 hours by default; see Keep Monitors Awake. While it is on, On until with the end time and Stop now appear beside the label. Saved with Save; a new duration applies from the next time the item is chosen.
Use the keyboard's brightness keys	The keyboard's Brightness Up/Down keys step every external monitor by 10%; see Keyboard Brightness Keys. Saved with Save. Disabled by default.
Pause while connected through Remote Desktop	Leaves the monitors alone while the session is viewed remotely; see Remote Desktop. Saved with Save. Enabled by default.
Start with Windows	Launches Not Too Bright in the tray when you sign in to Windows, through a per-user startup entry (no administrator rights needed). An entry disabled in Task Manager's startup apps shows as off; turning the option on re-enables it. Saved with Save. Disabled by default.
Automatically check for updates	Checks at startup, whenever Configure opens, and every 60 minutes. A newer build opens Configure and its update prompt. Enabled by default.
Update (button)	Checks the repository for a newer build right now and shows the result; see Updates.
Enable debug logging	Appends timestamped diagnostic events to %LOCALAPPDATA%\NotTooBright\debug.log (rotated at ~1 MB): Windows version and settings, every adapter and monitor Windows reports, EDID identity, each DDC/CI call with its result, error code and duration (including the monitor's capabilities string when a probe fails), each call to Windows' brightness control for a built-in display and every level Windows reports for it, mode changes, applied values, overlay changes, and dialog actions. Attach it when reporting a monitor that is not controlled. Disabled by default.

The footer displays the application version.

Where Settings Live

Everything is stored per user in the Windows Registry; nothing is written next to the executable, so it can run from any folder.

Location	Contents
HKCU\SOFTWARE\JPIT\NotTooBright	Global settings: the extended-range option, the schedule and its pause deadline, the tray menu target and preset levels, the keep-awake duration and end time, the brightness keys option, the Remote Desktop pause, update checking and the ignored update version, debug logging
HKCU\SOFTWARE\JPIT\NotTooBright\Monitors\<monitor id>	Per-monitor values: brightness, software-only, hidden, scheduled, original brightness
HKCU\Software\Microsoft\Windows\CurrentVersion\Run, value NotTooBright	The Start with Windows entry (the quoted path of the executable), only while that option is on
%LOCALAPPDATA%\NotTooBright\debug.log	The debug log, only when logging is enabled
%TEMP%\NotTooBright\, %TEMP%\NotTooBright.WebView2\	The extracted WebView2 loader and the dialog's browser profile; safe to delete
%TEMP%\NotTooBright-download-*.exe, %TEMP%\NotTooBright-updater-*.exe	Staged update and the short-lived updater copy; removed when an update finishes

The last Detect from IP answer (IpLocation* values under the same key) is kept so the services are asked at most once an hour.

Deleting the HKCU\SOFTWARE\JPIT\NotTooBright key returns the application to its factory state; turn Start with Windows off first (or delete its Run value) if the application should no longer start at sign-in.

Limitations

• Software dimming blends the picture toward black; it cannot reduce the backlight, so contrast drops as you dim, and the mouse cursor stays bright.
• Windows keeps some of its own surfaces (Start menu, notification center, secure desktop prompts) above every application window; those are not dimmed by the overlay. Hardware control has no such limit.
• DDC/CI must be enabled in the monitor's menu and pass through whatever sits between the computer and the monitor; many docks and KVM switches do not forward it.
• On a built-in display, Windows' adaptive brightness (Change brightness automatically when lighting changes) keeps adjusting the level, and each of its adjustments counts as a manual change that pauses the schedule. Turn it off if the schedule should control that display.
• Started inside a Remote Desktop session, the application knows no monitors until the session is back at the console; the dialog says so.

Building from Source

The application is cross-compiled from Linux. The build host needs:

• MinGW-w64 (x86_64-w64-mingw32-gcc and x86_64-w64-mingw32-windres)
• Node.js and npm (for the configuration UI in assets/)
• ImageMagick (optional, only for make icon)

# Build everything: configuration UI, resources, executable
make

# Output: releases/NotTooBright.exe (single self-contained file)

The MinGW toolchain is taken from the PATH by default. To use a toolchain installed elsewhere, either pass a prefix on the command line:

make CROSS=/opt/mingw-w64/bin/x86_64-w64-mingw32-

or create an untracked local.mk next to the Makefile with the same setting, so plain make picks it up on that machine:

CROSS = /opt/mingw-w64/bin/x86_64-w64-mingw32-

Other targets:

make frontend   # build only the configuration UI (assets/dist/index.html)
make icon       # regenerate assets/icon.ico from assets/icon.svg
make clean      # remove objects and the built UI
make clean-all  # additionally remove node_modules and releases/

The WebView2 COM interfaces used by the configuration dialog are declared directly in NotTooBright.c, so no WebView2 SDK download is required. The build is reproducible: the same sources produce a byte-identical executable.

Project Structure

Path	Description
NotTooBright.c	Application source (monitor detection, DDC/CI worker, dimming overlays, schedule, tray icon, configuration dialog host, settings)
NotTooBright.manifest	DPI awareness and supported OS manifest, embedded as a resource
resource.rc, resource.h	Resource script: icon, manifest, version info, embedded UI and loader
version.h	Single source of truth for the application version
assets/	Configuration UI (React, Vite, Tailwind), the icon, the screenshot, and WebView2Loader.dll
releases/	Build output (NotTooBright.exe)

Tray recovery checks

Tray startup/recovery regression checks: python3 tests/test_tray_registration.py. These simulate delayed Explorer readiness, taskbar recreation, current icon/tooltip recovery, and shutdown with a retry already queued; a live sign-in/restart smoke test requires Windows.

License

MIT