Adjust Brightness on Second Monitor: DMT vs Twinkle Tray
Windows gives you no slider for external monitors. Two free tools fix that — here’s an honest comparison.
Why there’s no slider
External monitors need DDC/CI
Laptop screens get a Windows slider; desktop monitors don’t. Both DMT and Twinkle Tray talk to monitors over the DDC/CI protocol — which must be enabled in your monitor’s own OSD menu first.
Option A — DMT (v2.9+)
- Enable DDC/CI in each monitor’s OSD menu.
- Open DMT → General/Monitor and use the brightness/contrast sliders.
- Bonus: it’s the same app already handling your cursor and windows — one tray icon total.
Option B — Twinkle Tray (dedicated tool)
When Twinkle Tray wins
Free and open-source, with a modern Windows 11-style flyout, per-monitor sliders, brightness schedules (dim at 8 PM automatically), and hotkeys. If brightness is all you care about, it’s the nicer tool.
Pro tips
- Many users run both: Twinkle Tray for brightness schedules, DMT for cursor/window control.
- Pair software dimming with a monitor light bar for late-night sessions.
Frequently Asked Questions
How do I adjust brightness on my second monitor?
Two free options: DMT’s Monitor module (v2.9+) adjusts brightness/contrast over DDC/CI from software, or Twinkle Tray, a dedicated open-source brightness tool with per-monitor sliders and scheduling.
Why is there no brightness slider for my external monitor?
Windows only shows a brightness slider for built-in laptop displays. External monitors need DDC/CI commands — which is exactly what DMT and Twinkle Tray send.
DMT vs Twinkle Tray for brightness?
Twinkle Tray is the better pure brightness tool (nicer UI, schedules, per-monitor sliders). DMT’s advantage: brightness lives alongside cursor lock, window hotkeys, and everything else in one tiny package.
Ready to try Dual Monitor Tools?
Free, open-source, and portable. Get version 2.13 now.
Download DMT v2.13 (Free)