Finally I had some more time to this and finished the floorplan and lights (the actual light sources still missing and need to be drawn though).
Indeed there are different needs for every (battle)map and therefore when this will be finished I will include two different versions. One with specific lights and shadows and another "natural" one without any special effects. I have already created the map this in mind and all special things (light sources, items etc) can be removed in just few clicks.
I had challenges especially creating the shadows and finding a reasonable way to make corrections to them if (and when) I change the corridor layouts. The only solution I could come up with is to make the layout first and worry about the lighting afterwards. But that's not how I work. I couldn't keep my hands away from the shadows and I constantly had to recreate something I had finished 10min ago.
That is true. I will modify the shadows and I also need to pay attention on indirect light (amount of light and the color) in the corridors. One example of this is the orange light in the corridor from the fire. Even though the direct light doesn't hit the floor or the walls all the way, they still have a hint of orange in them.
Finally I had some more time to this and finished the floorplan and lights (the actual light sources still missing and need to be drawn though).
Added a lantern and draw a holder to it. Will be adding more items next time.
As a player I know as soon as you see a checkerboard pattern on the floor you should turn and leave the dungeon. There could be chess puzzles.
I admit I have used checkerboard puzzles few times myself and players learn to notice them rather easily. But then I have created many potential places for such puzzle or trap and not implement any. Players lower their guard after few games and then you are ready for yet another checkerboard puzzle.
It's also not out of theme with the "regular" hall floors since those are also checker board, I wouldn't think players would be that cautious. Or rather I don't think players would be needlessly more cautious than they invariably are already.