HDR Monitor Guide: Local Dimming & Specs

High Dynamic Range (HDR) is one of the most significant advancements in display technology. Unlike resolution jumps (like 1440p to 4K), which increase pixel count, HDR fundamentally improves pixel quality.

It delivers a much wider contrast ratio (the difference between the brightest highlights and the deepest shadows) along with a broader, more lifelike range of colors. However, because HDR has become a major marketing buzzword, many monitors claim HDR support without possessing the hardware required to display it properly.

What is High Dynamic Range (HDR)?

In standard displays (known as Standard Dynamic Range or SDR), the dynamic range is limited. SDR content is typically mastered to a maximum brightness of 100 nits (cd/m²) and fits within the relatively narrow sRGB color space. HDR expands this envelope significantly.

HDR content is mastered at 1,000 nits, 4,000 nits, or even higher, and is paired with wide color gamuts (typically DCI-P3 or Rec. 2020) and 10-bit color depth (1.07 billion colors). This allows displays to show blinding sun glares, deep ink-like shadows, and highly saturated colors simultaneously without losing detail.

Hardware requirements: Brightness, contrast, and local dimming

For a monitor to render HDR, it must have three key hardware capabilities:

• High Peak Brightness: The monitor must be able to push small areas of the screen (specular highlights) to high luminance values. While SDR operates around 100-250 nits, true HDR requires peaks of 600 to 1,000+ nits.
• Wide Color Gamut & 10-bit Depth: HDR requires a display to cover at least 90% of the DCI-P3 color gamut and display smooth gradients using 10-bit color depth to avoid color banding.
• Local Dimming: This is the most critical element. In traditional LCDs, a single backlight shines behind the entire panel. To make a small star shine in a dark sky, the monitor must turn up the backlight, which makes the entire sky look gray. Local dimming solves this by dividing the backlight into zones that can dim or turn off independently.

Backlight technologies compared

The method a monitor uses to dim its screen determines its HDR performance:

• Edge-Lit Local Dimming: LEDs are located along the edges of the frame. The screen is divided into a handful of vertical columns (usually 8 to 16). This is the cheapest method but leads to severe “blooming” (columns of light visible around bright objects).
• Full-Array Local Dimming (FALD) & Mini-LED: Hundreds or thousands of tiny LEDs sit directly behind the LCD panel, grouped into independent zones (ranging from 384 to over 2,000 zones). This allows tight control over bright and dark spots, enabling excellent HDR contrast with minimal blooming.
• OLED (Self-Emissive): OLED (Organic LED) and QD-OLED monitors do not use a backlight. Instead, every single pixel (over 8 million in a 4K screen) generates its own light and can turn off completely. This provides an infinite contrast ratio, absolute black levels, and zero blooming, making OLED the gold standard for HDR.

Understanding HDR format standards

There are several competing HDR standards that dictate how color and brightness metadata is sent from your computer or console to the display:

VESA DisplayHDR tiers explained

To clear up market confusion, VESA (Video Electronics Standards Association) created the DisplayHDR certification program. When buying a monitor, these tiers give a reliable indication of its HDR capabilities:

• DisplayHDR 400: The lowest tier. Requires only 400 nits of peak brightness, global dimming (no local dimming), and standard sRGB color gamut. This is essentially an SDR monitor that can accept an HDR signal. Performance is often disappointing.
• DisplayHDR 600: Requires 600 nits peak brightness, wide color gamut (90% DCI-P3), 10-bit depth, and mandatory local dimming (usually edge-lit). This represents the entry point for noticeable HDR performance.
• DisplayHDR 1000 & 1400: High-end LCD tiers. Require 1,000 or 1,400 nits peak brightness, wide gamuts, and high-performance local dimming (almost always Mini-LED/FALD). These deliver extremely bright, punchy HDR highlights.
• DisplayHDR True Black 400 / 500 / 600: Specialized tiers for OLED and Micro-LED displays. Because OLED pixels turn off completely, their black level is virtually 0 nits. Therefore, they do not need 1,000 nits of peak brightness to achieve an outstanding contrast ratio. DisplayHDR True Black certifies that a display has perfect blacks and excellent highlight response.

Setting up HDR on a PC

Windows has historically struggled with HDR handling. To get the best results:

1. Enable HDR in Windows settings under System > Display > Use HDR.
2. Download the official Windows HDR Calibration App from the Microsoft Store. Run it to calibrate your monitor’s minimum black and maximum white clip points. This prevents blown-out highlights and crushed shadows.
3. Adjust the SDR Content Brightness slider. This controls how bright non-HDR elements (like web browsers and word processors) appear when HDR mode is active.

Frequently asked questions