Onyx Boox Poke5P User Manual page 13

Dark Color Enhancement
This function turns darker colors
to black and is generally used for
enhancing foreground colors, or
light-colored pages, such as colorful icons, and low-quality
scanned PDFs.
Light Color Filter
This function turns light page
colors to white and is normally
used to whiten the background
colors.
More Settings
Customize more optimization settings for a better user
experience by going to E Ink Center/ App Optimization or
long-press an app's icon to choose " Optimize".