pre shading is a well known effect for gunpla, it gives your model a nice darker look on the edges making your kit stand out more.

to achieve this effect, start with spraying a thin layer of primer on the model.

this would also count as our undercoat, this will give the gunpla a certain color before proceeding further.

next pour in  the color your going to use for pre shading, i would be applying black in this tutorial, but i prefer spraying a darker shade of the base coat to give it a more subtile effect.

keep your airbrush at a low psi as you spray, it makes hitting the details easier.

you can first start by practicing on paper before doing the real thing.

its all up to you on what you want to pre shade, i would be going for corners, holes, areas that could be casted by a shadow, and other details.

once the paint has finally cured you can now move on to your base coat. keep an even layer on each piece to keep the shading the same in all areas.

and thats how to pre shade your gundam kits, till next time!