"The colour enhancement card is an adapter card which, when used with specially written programs or with certains application programs with appropriate screen drivers, can enhance your screen display dramatically"

The above photograph is a working recreation using the known schematic with a layout roughly equal to the graphical represention in the service manual.
I have never come across a photograph or a surviving card. Usage is therefore unknown.

The onboard video memory of the X series with the version 2 I/O board was 256kb. The Paradise PVGA1A IC can be run with 1MB. This can be achieved with the Colour Enhancement Card. The example shown here is the full 1mb. In this configuration it disabled the existing vidceo memory. Options existed to have the card populated with just 256kb to add to the existing giving 512kb.

Additional graphics modes included:
800x600 16 colours
640x480 256 colours

Drivers were included for various CAD applications.

The installation guide is available here

It connects to the I/O board via the 96 way Harting connector