Mixed Raster Content (MRC) compression is designed to create compact PDF files from image-only source files containing both text and color or grayscale pictures or backgrounds, by separating the elements and applying optimized compression to each of them.
This setting is applied during WriteDocument() when OutputManager.Format is:
By default, this setting is Off, but can be enabled by setting the Recognition.MrcQuality property to a supported grade:
For example, to export recognition output to an Image Over Text PDF using medium MRC quality: