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description: monoImageFilter
---

# MonoImageFilter

| Method Name     | Argument Name | Argument Type                                 |
| --------------- | ------------- | --------------------------------------------- |
| monoImageFilter | filter        | Mostafaznv\PdfOptimizer\Enums\MonoImageFilter |

Specifies the compression filter to be used for monochrome images. Must be one of the following values:

* **CCITTFaxEncode:** Selects CCITT Group 3 or 4 facsimile encoding
* **FlateEncode:** Selects Flate (ZIP) compression
* **RunLengthEncode:** Selects run length encoding



