This is very good sample of the advanced color line art. Similar method is used by one illustrator from UK, can't
remember name in the moment. This is nice!!! And I like that colors are close to the real match. You have good
calibrated monitor as I can see
So in this method of camouflage color presenting you don't need to do any more. As you know this type of art
preserve all of the basic drawings outline and camouflage is apply with a minimun of the shades and highlight.
Identical as in the monochrome line art up to the '80 but in this way color is used.
Any way, you have a principal sense for the shape of object on the plane and can fight with the light direction.
From my point of view you can free go to the next step full color art. But I have to note that creating of the
basic layers in full color art need over a week per type of plane and need deep search. So when you start with
practice use some well nkown planes with a lot of images. Like this Mosquito.