Yes, cel painting is, in a word, painful.  I went 
to art college and we had to make a 45 frame 
animation that looped, AND we had to hand paint 
each cel.  God, to not bleed over lines and to 
not have thin places, you just go through the 
most hateful process.  I did a great cel a long 
time ago, not an anime character, and it took me 
a week and half to finish it, just to let it dry 
so I could put the next layer on!  If anyone out 
there thinks painting these cels is easy, try it 
once!  I guarantee you will have so much more 
pleasure for your own cels if you have tried to 
make one yourself. 

Gorgeous pic though, I like their faces!