This is one of the most stunning MLP pieces I've ever seen. Nightmare Moon's expression just gives me chills, while Celestia's makes me sad, and that's not something that's easy to do. A fantastic job!
I absolutely love this. The colors, the expressions, everything just has this epic feel to it. And, oh, the dramatic irony, it's so delicious. With the presence of the EoH we all know how this battle will turn out but the defiance in NMM's eyes, so cocksure and prideful, I tingle at the thought of being able to watch this battle unfold. I've always thought that NMM (or Luna in general) must have had more magical talent than Celestia seeing as how she was able to single-handedly overthrow Cel (even before becoming NMM) and that Cel had to resort to using the EoH in order to defeat her, but I digress.
Now on to my critique. Fortunately I have only one problem with this picture. Technically the battle took place after NMM had completely covered the world in darkness. Now, if that just meant she covered the world in clouds or something than she is fine, but if that's the case she should really consider a name change and possibly a different cutie mark.
Well personally I always believed she simply did what she did in the pilot episodes aka bring forth eternal night. This is why I called the image 'dawn'. The sun rises as Celestia returns to bring an end to the dark night and begin the day / night cycle anew. Originally the image had a more dark blue night-sky feel, but I guess I failed at the transition between night and dawn, heh.
Oh, i did indeed sketch this beforehand. In fact, I went through the trouble of making proper clean lineart, but then I realized it wouldn't cut it. I sketch all my images before I start to paint, but they usually end up in quite different places. This is why I prefer painting over simply colouring lineart. The paintwork is like a lump of clay that I can shape like I want, while lineart is more like a pottery that I paint. No matter what I do I'll have to make a new pot if I want to have the shape different.
Sadly I no longer have the sketch for this piece, as I disliked it enough to not save it as a separate file. Celestia especially looked very differently in the sketch and lineart. I am very happy that I decided to paint a new one instead, haha. I'll remember to keep my sketches for future paintings.