Paul Francis :
Your off the shelf filter looks like something out of Heavy Metal :)

Rawnrr : Keep your pet on a leash so he don't eat my thread ;)

Vintorix :
Raiden.D has a good example of converting 3D in to 2D.

http://www.zbrushcentral.com/showthread.php?167492-Franz_WIP
2nd page he has a you tube ,how it was done.
Think Raiden.D would agree with Philebus about lights.

You can use shaders also.
http://www.pixologic.com/zbrush/features/ZBrush4R5/render-and-materials/
zBrush has a lot more shaders.
a lot will make multiple renders for 2D and 3D and layer them.

If you don't have lights n shaders that will do all this
ya can turn the 256 colors down to 16,32 some where low.
Looks like what Paul Francis did with The come with me.
Then ya could blend it with the blur brush.
paint over top it in a new layer.You could do this in Gimp.

One thing I've noticed painting will not be textured as much as renders.
All the cloths in the sistine chapel are solid colored clothes.

Think at times multiple renders ,layers and masking might be helpful.

 

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