I completed a map previously and while working over story ideas for it, began building on an idea of crossing between planes within the dungeon. Having one in the mortal realm and one in the ethereal/astral one.
Ended up using this same layout for part but opening up new areas and also having it like it was drifting apart in space.

Process started with drawing pen and paper and then colouring on the computer. Much of the main colour layers being painted to add variation and colour, and a few shadow and lighting layers on top.
etheral dungeon.jpg

And a pic of the completed linework
20190320_222142.jpg