> For the complete documentation index, see [llms.txt](https://documentation.qure.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://documentation.qure.ai/users-manual/qure.ai-app-users-manual/qure.ai-app-features/windows-mac-os-app-ui/qure.ai-app-viewer/dicom-viewer/tool/window-level.md).

# Window/Level

**Window/Level** allows the user to change the contrast/brightness of the image. To enable freeform adjustment, click the tool; after that, click and drag on the viewport to freely modify the window/level. Click and drag up/down to change the contrast, and left/right to change the brightness.

Click on the **Window/Level** drop-down arrow and select the predefined Window/Level settings for the appropriate image.

<figure><img src="https://files.gitbook.com/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FZoJKHhnFYNEcdzbCHz2j%2Fuploads%2FG9HsJSKEIO0NkHIvyMUQ%2FImage%2019-12-22%20at%202.40%20PM.jpeg?alt=media&#x26;token=0594f787-ca9d-4d8d-8b34-f265e8b3d26b" alt="" width="375"><figcaption></figcaption></figure>