I forgot to mention back there that it’s still a WIP, lol… Anyway, here’s the finished render. Cycles, smoke effects and finishing in GIMP.
This is super awesome! Love it man. Great colors and execution.
Wow! I need to work on my nodes. Such cool looking effects.
Question: what was gimp used for?! Was it the vignette effect?
Thanks! Not too much procedural thingies here actually, mainly for the pages effect and tendril emission. GIMP is mostly for the black smoke effect and to add some glow, also for the sparks (too lazy to do particles, lol). Here are the raw render before post-pro, and the clay render.
WOW - That is cool! Love the effects.
I never think of doing any additional touchups outside of Blender. I still have enough time getting Blender todo what I want it todo without worrying about another program as well!!
Well, you can also use the compositor for some cases. Here’s a simple example of me insisting on doing all things w/o using other program : https://blenderartists.org/t/nine-breakdown/698049/3
Depends on the scene etc. some effects are much easier (and faster) to do in post-pro in another program rather than rely solely on Blender (for example the bokeh and glow/blur in the example can be easily made in 2d program), while on other case it might be enough just using Blender (and compositor). So, it’s your choice! 
I like looking at node setups like this even if I don’t understand fully what is going on but I try.
It surprises me how many different ways there are to get the same result.
Very cool