Mavis Portrait (Patreon)

Paint tool Sai
I used a lot of tricks here
I turned the finished painting into a line art
then multiply/screen over the line art to make it red
and another blue then made a chromatic aberration
by incrementally moving the blue and red line art layers
to the left or right(depends on what works)
this also helps to blur around the edges
Overlay works in conjunction with greys
that are Opaque Brush applied over the skin
its almost unnoticeable while you do it
but has an effect,ususaly you don't think
greys would go over skin
its a 30 -70% grey but applied very subtly
and blended.