Occurrence

When I convert or export my grid file into a Geotiff, it becomes grayscale and loses it's colouring scheme.

Solution

This is due to the Geotiff grid format being a multi-banded format. 

If a single banded grid is converted to this, it will become grayscale as it does not contain 3 RGB bands.

You can use the Grid Utilties>Create RGB tool to create a multi-banded Geotiff grid.

Alternatively the surface grid can be saved as a standard Geotiff raster file using Discover>Map Window>Convert Map to Registered Raster.