1600 nits. No private APIs.

macOS reserves XDR's full brightness for HDR video playback only. WitzLyte bypasses that restriction, placing a CAMetalLayer over a borderless, click-through NSWindow to drive the display at full rated nits on demand.

To dim below the OS brightness floor, the Metal layer renders a solid black frame and sets blendMode = .multiply . Screen color values are multiplied by a near-zero factor, effective brightness drops far below the 500-nit hardware minimum without touching display registers or private frameworks.

Lives entirely in the menu bar. Brightness slider covers the full 0–1600 nit equivalent range. One-click toggle. Bindable keyboard shortcut for instant access during creative work, color grading, or low-light use.

Every technique is public-framework only: AppKit, Metal, Core Animation. The app runs inside the App Sandbox and can be distributed outside the Mac App Store without entitlement exceptions. The trick is architectural, not privileged.

A NSWindow is created with .borderless style mask, level = .screenSaver , and ignoresMouseEvents = true , it sits above all content, invisible to interaction.

A CAMetalLayer fills the window's content view. For brightness boost, it stays transparent. For sub-floor dimming, it renders an opaque black frame each display refresh via a Metal command buffer.

The layer's compositing blend mode is set to kCGBlendModeMultiply . A near-zero alpha on the black frame multiplies all display pixels, effectively lowering luminance far below hardware minimums without write access to display hardware.