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CRT Scanlines and Shadow Masks in ShaderGlass

Scanlines and shadow-mask patterns approximate CRT subpixel and beam structure. The right strength depends on output resolution and viewing distance.

Before you begin

Use Windows 10 version 2004 (build 19041) or Windows 11 and a DirectX 11-capable GPU. Confirm the source window or capture device works without additional post-processing. The exact labels can differ between ShaderGlass versions and operating modes.

Step-by-step workflow

1. Choose a basic CRT shader and note the initial scanline pattern.
2. Compare the scene at its intended aspect ratio before adjusting fine detail.
3. If available, adjust scanline intensity or mask strength in small increments.
4. Recheck bright and dark scenes and save the usable profile.

Important details and limitations

Heavy masks can darken images considerably on ordinary LCD monitors.

Aggressive scanline patterns may shimmer when scaled to uneven pixel dimensions.

Some CRT presets expose no mask controls; pick another shader family instead.

How to verify the result

Compare the processed scene with the same source shown without ShaderGlass. Watch for clipping, unexpected color changes, black regions and input lag. Keep one parameter fixed at a time while troubleshooting. For version-dependent settings, refer to the developer manual instead of relying on old screenshots.

Questions and answers

Are scanlines suitable for desktop text?

Usually a lighter treatment is easier to read than a strong retro mask.

Why does the screen get darker?

A scanline or mask filter intentionally reduces some pixel luminance.

Related guide: Crt Shaders · All ShaderGlass guides · Windows download information.

Technical reference: Developer manual. This guide explains settings and does not alter the ShaderGlass application or its license.