Windowing button is used to adjust image contrast and brightness (Level and Window values). You can change the brightness using the mouse or from the menu.
For changing the brightness with mouse, assign the mouse button to Windowing function
Hold down the assigned button and drag the mouse upwards or downwards (to change Level values), and right or left to change Window values.
The windowing values may be applied for the same series in different viewports. By default, this feature is disabled, and you should use the Sync Windowing for Same Series menu to enable it.
Sync Windowing feature is also applicable for the reconstructed orthogonal series.
Also, you can click the red triangle on the right of the button and select the windowing from the menu:
The brightness level menu consists of static and dynamic elements - groups and options. Dynamic menu elements are only displayed if they are applicable to the active image.
Windowing Menu Elements
Windowing controls the brightness and contrast of the image. To access windowing options, click W or select Windowing from the toolbar.
Auto
Automatically adjusts brightness and contrast based on the image. Applied by default if no other windowing options are available.
Window & Level presets
A list of brightness/contrast presets pulled directly from the image's DICOM data. The first preset in the list is applied automatically when available.
VOI LUT (non-linear transformation)
Only appears if the image contains VOI LUT data. Unlike standard windowing which uses a simple brightness/contrast range, VOI LUT applies a curve that gives more weight to the values that matter most in the image. The first available configuration is applied automatically.
Color LUT (color palette)
Only appears if the image contains color palette data. The palette is applied automatically when the study loads. If you change the windowing level afterwards, you'll need to click Color Palette again to reapply it.
Custom Windowing
Shows additional windowing presets specific to the imaging modality, if any are available.
Invert
Flips the image from dark-on-light to light-on-dark, or vice versa.
Sync Windowing
Applies your windowing settings across all viewports showing the same series, including MPR projections. Enabled when the sync icon is highlighted. This setting is saved in your browser and only applies to that browser.
Color Palette Selection
Applies a color palette to the active viewport. Enabled when the icon on the left of the menu is highlighted.