Dither Effect Pro

A UXP plugin for Adobe Photoshop that applies classic dithering algorithms to your images. Create retro, pixel-art, and stylized effects with precise control.

Features

• 8 Dithering Algorithms

  • Floyd-Steinberg (classic error diffusion)
  • Atkinson (Mac classic aesthetic)
  • Ordered Bayer 4x4 & 8x8 (crosshatch patterns)
  • Random Noise (stipple effect)
  • Halftone (print-style dots)
  • Sierra Lite (fast error diffusion)
  • Stucki (high-quality error diffusion)

• 5 Color Modes

  • Black & White
  • Grayscale (4 or 8 levels)
  • RGB Web Safe (216 colors)
  • Custom Palette (6 user-defined colors)

• Additional Controls

  • Strength slider (0-100%)
  • Scale slider (1-16x) for chunky pixel effects on high-res images
  • Preserve Transparency option
  • Halftone-specific dot size and angle controls

Installation

Via UXP Developer Tool (Development)

1. Download or clone this repository
2. Open Adobe Photoshop 2022 or later
3. Go to Plugins → Development → UXP Developer Tool
4. Click Add Plugin and select the manifest.json file
5. Click Load to activate the plugin

Prerequisites

Make sure these Photoshop settings are enabled:

• Edit → Preferences → Plugins → Enable Developer Mode ✓
• Edit → Preferences → Plugins → Enable Generator ✓

Usage

1. Open an image in Photoshop
2. Select the layer you want to dither
3. Open Plugins → Dither Effect Pro
4. Choose your algorithm and color mode
5. Adjust strength and scale as desired
6. Click Apply Dither
7. Use Undo or Ctrl/Cmd+Z to revert

Tips

• High-resolution images: Use the Scale slider to create visible dither patterns. Scale 4-8x works well for most HD images.
• Retro game look: Use Ordered Bayer with Black & White or limited Grayscale
• Mac classic style: Atkinson algorithm with Black & White
• Print effect: Halftone with adjusted dot size and angle
• Custom palettes: Select "Custom Palette" color mode to use your own 6-color palette

Settings

Click the ⚙️ gear icon to access settings:

• Limit image size to 50 MP - Enabled by default. Prevents memory exhaustion when processing very large images. Disable at your own risk for images larger than ~7000x7000 pixels.

Requirements

• Adobe Photoshop 2022 (v23.3) or later
• macOS or Windows

Known Issues

• Very large images (>50 megapixels) may cause instability or crashes
• Processing time increases with image size and scale factor
• Smart Objects should be rasterized before applying the effect

Development

See devlog-history.md for detailed development history and technical decisions.

Building from Source

No build step required - this is a pure UXP plugin with vanilla JavaScript.

File Structure

photoshop-dither-plugin/
├── manifest.json        # UXP plugin configuration
├── index.html           # Plugin UI
├── index.js             # Plugin logic and algorithms
├── README.md            # This file
└── devlog-history.md    # Development history (for contributors)

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Test with UXP Developer Tool
5. Submit a pull request

Algorithm Details

Algorithm	Type	Best For
Floyd-Steinberg	Error diffusion	General purpose, smooth gradients
Atkinson	Error diffusion	High contrast, retro Mac look
Ordered Bayer	Threshold matrix	Patterns, game graphics
Random Noise	Random threshold	Stipple, grain effects
Halftone	Pattern-based	Print simulation
Sierra Lite	Error diffusion	Fast processing
Stucki	Error diffusion	High quality, subtle

License

MIT License - feel free to use, modify, and distribute.

Credits

Developed with assistance from Claude (Anthropic).

Changelog

v1.0.0

• Initial release
• 8 dithering algorithms
• 5 color modes including custom palette
• Scale feature for high-res images
• Memory safety limits with toggle
• Settings panel