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Sub-Pixel Test

1-pixel alternating patterns reveal sub-pixel layout (RGB vs BGR), ClearType alignment, and text rendering quality on your display.

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What are sub-pixels?

Each pixel on an LCD or OLED is made up of sub-pixels, typically red, green, and blue elements arranged in a pattern. The most common arrangement is RGB stripe, where sub-pixels run vertically. Some panels use BGR (blue-green-red), pentagon/PenTile patterns (common in OLED), or other layouts.

Why sub-pixel layout matters

ClearType and sub-pixel text rendering on Windows uses the sub-pixel arrangement to sharpen text at small sizes. If ClearType is configured for RGB but your panel uses BGR, text will show colored fringing. macOS uses greyscale anti-aliasing which is layout-agnostic.

How to check your sub-pixel layout

  1. Open the RGB Fringe pattern on this tool.
  2. Zoom in to 100% on your screen.
  3. Look at the order of red/green/blue strips - if red is on the left with green/blue following, it is RGB. Reverse means BGR.
  4. PenTile OLED panels show diamond-shaped sub-pixels instead of stripes.

Small text rendering

Open the Small Text pattern and look at 9px and 11px text. On a well-calibrated high-PPI display, each letter should be crisp with no colored halos. Colored fringing (red/blue outlines on letters) indicates ClearType mis-configuration or sub-pixel mismatch.

For more display tests, see Sharpness Test and Text Clarity.