> ## Documentation Index
> Fetch the complete documentation index at: https://docs.comfy.org/llms.txt
> Use this file to discover all available pages before exploring further.

# FreeU - ComfyUI Built-in Node Documentation

> The FreeU node applies frequency-domain modifications to a model's output blocks to enhance image generation quality.

The FreeU node applies frequency-domain modifications to a model's output blocks to enhance image generation quality. It works by scaling different channel groups and applying Fourier filtering to specific feature maps, allowing for fine-tuned control over the model's behavior during the generation process.

## Inputs

| Parameter | Description | Data Type | Required | Range |
| - | - | - | - | - |
| `model` | The model to apply FreeU modifications to | MODEL | Yes | - |
| `b1` | Backbone scaling factor applied to feature maps with model\_channels × 4 channels (default: 1.1). Marked as an advanced setting. | FLOAT | Yes | 0.0 - 10.0 |
| `b2` | Backbone scaling factor applied to feature maps with model\_channels × 2 channels (default: 1.2). Marked as an advanced setting. | FLOAT | Yes | 0.0 - 10.0 |
| `s1` | Skip connection scaling factor applied to feature maps with model\_channels × 4 channels (default: 0.9). Marked as an advanced setting. | FLOAT | Yes | 0.0 - 10.0 |
| `s2` | Skip connection scaling factor applied to feature maps with model\_channels × 2 channels (default: 0.2). Marked as an advanced setting. | FLOAT | Yes | 0.0 - 10.0 |

Note: FreeU adjustments are applied only to feature maps whose channel count equals model\_channels × 4 (using `b1` and `s1`) or model\_channels × 2 (using `b2` and `s2`). The Fourier filter scales only the central low-frequency region (threshold of 1) of the skip connection feature maps; all other frequency components remain unchanged. All four scaling parameters accept values between 0.0 and 10.0 in steps of 0.01.

## Outputs

| Output Name | Description | Data Type |
| - | - | - |
| `model` | The modified model with FreeU patches applied | MODEL |

> This documentation was AI-generated. If you find any errors or have suggestions for improvement, please feel free to contribute! [Edit on GitHub](https://github.com/Comfy-Org/embedded-docs/blob/main/comfyui_embedded_docs/docs/FreeU/en.md)

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