Here's the lineart of Ryuko Matoi from Kill La Kill Will take it to finish like the Midna Fan Art that I did. I'll do my best to record the process every step of the way. This is a pretty clean line art so hopefully it looks consistent throughout the process to the end. It's my interpretation and my version of the character in my own style.
please share this image around for support! Thanks!
I was also interested in this. I can lead you to some guess of mine.
Zeronis loves to uses anaglyph filter on his girls, whether it's on grayscale or color version, he apparently added some anaglyph here and there and enhanced the anaglyph based with other colors.
I can't tell whether the enhancing of the colors is automatically done or not but here you can see mostly black lines (his base drawing), green/purple lines (the anaglyph filter), and some blue going here and there which appears to be done by blending a duplicated version of the base drawing with another color.
You can also see anaglyph is being used by zooming in his work. You can see some tweaks herehereherehere
See the parts where the colors kinda tweak ? zoom in simple shapes or edges like hair. Zoom in their eyes. Hell even in Grayscaled Vi you can see colors in her eyes while he said it was only a gray version. A more obvious use of anaglyph is the morgana skin though here Try to zoom on her metal parts, it's the most obvious Green/Purple use of anaglyph here. And it still looks cool.
I didn't check others because this much is enough for me to study.
I think the reason he uses anaglyph on his girls is because he always go for a blurry/glossy render. But if you blur it all you can't see much, so the use of anaglyph helps things to pop out better even though some parts are blurry.
Just my guess on this matter. Hoping I helped a little :3
... But on a second thought I think sometimes he actually uses anaglyph and on some other time it's something else. Sorry I can't give you the best answer.
The fact that on some pictures the edges are really hard could mean that he could have select an area or a color and copy paste couple of times. Each times it is copied it would be moved and changed color to get a some sort of anaglyph effect. I can't know for sure what he did.
Edit: or after further research, maybe he just created some chromatic aberration... which sounds lot more simple to do once you know about it