> For the complete documentation index, see [llms.txt](https://mostafaznv.gitbook.io/pdf-optimizer/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mostafaznv.gitbook.io/pdf-optimizer/advanced-usage/configuring-ghostscript/monoimagefilter.md).

# 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