Some WIPS for chamber[link]
I had a very clear idea on the concept when I started - the figure inside a nautilus shell, but also joined with the shell, the spiral and pose defining the composition. What I was still pretty vague on was the background and how to ground him and the shell in space. It only came together towards the very end!
I started with the figure, I really wanted to nail that long extended arm as it defines the pose. I built up the shell next, rather tedious - and then I ended up losing the whole bottom part when I decided to add the water
The spiral on the body was another difficult part - everything I tried looked forced, in the end I just kept it subtle.
Lots of overlay modes to create light. I usually stick with the same two or three brushes for most of my painting, but for the background I went crazy and tried a bunch I never use - it was fun!