ComfyUI-Dither

A custom node pack for ComfyUI that applies high-quality image dithering (Atkinson and Halftone), including channel-split dithering for advanced RGB/CMYK printing effects.

Nodes Included

1. Dither: A simple node that applies dithering to the input image or batch.

   • Adjust threshold, contrast, brightness, gamma, and grain before dithering.
   • Choose between Atkinson error diffusion or Halftone grid patterns.
   • Set custom color1 and color2 (HEX strings) to map the output colors.
   • scale: Resize the image during processing (e.g., 2.0 for 200% resolution) to create high-res dithered outputs.

2. Dither by channel: An advanced node that splits the image into RGB or CMYK channels, applies dithering to each channel separately, and blends them back together.

   • Allows independent settings (method, threshold, contrast, scale, colors) for each channel.
   • Outputs each processed channel individually (CH1, CH2, CH3, CH4) and an OVERLAY composed of all channels blended together.
   • Choose blend_mode for the OVERLAY output (multiply, screen, overlay, add, darken, lighten).

Installation

Clone this repository into your ComfyUI/custom_nodes/ directory:

cd ComfyUI/custom_nodes/
git clone https://github.com/YOUR_GITHUB_USERNAME/ComfyUI-Dither.git

Install the requirements:

pip install -r ComfyUI-Dither/requirements.txt

(Note: Numba is highly recommended as it speeds up the Atkinson dithering process by 100x)