Red Free Filter

Turn on the red free filter to block red and blue wavelengths in color images.

Use the red free filter to block red and blue wavelengths of light in color images. The red free filter transforms images by applying a green filter and then converting the images to grayscale. This tool can be used to improve contrast in color retinal fundus images.

The Red Free Filter tool may need to be added to your toolbar or context menu. For more information, see Customize the toolbar or Customize the context menu or contact your system administrator.

NOTE: The red free filter image transformation will not be saved as part of a Presentation State or as a Key Object. That is, if you save an image that has the red free filter applied, the image will be saved in its original color format.

Select the image or series to apply the filter to.
On the toolbar, click

The filter is applied at the series level and the Red Free Filter indicator displays in the viewport. Note that if the series contains a mix of color and grayscale images, only the color images will have the Red Free Filter indicator as the filter is not applied to the grayscale images.