How To Paint A Multicolor Basecoat For More Realistic Gunpla Models

In this tutorial, Gunpla 101 contributor Miko AKA Mokiplamo shares his colorful take on adding depth and realism to your next modeling project. Read on to learn about the origins of his multicolor basecoat technique and see a fantastic example.

Hello again everyone, Moki from Mokiplamo here to share a new painting tutorial. Previously, we’ve talked about giving your models some extra oomph with the Black and White Technique, but what if you want to aim for realism? Today I’ll show you a unique type of pre-shading for Gunpla modeling. This technique involves applying a multicolor basecoat above your primer and beneath your paint in order to add more depth and variation. By incorporating this technique, you can add more kick to the final look, especially on models with a monotone color scheme. 

I need to thank several modelers for helping to make this tutorial as effective as it is now. The method I use begins with a demonstration of the Black Basing Technique as pioneered by Doog’s Models, which tries to bring a more varied and realistic finish to aircraft scale models. I was also inspired by the recent work of Makoto “Max” Watanabe of the figure company Max Factory, who is also one of the founding members of the Gunpla Master Grade line. Lately, Watanabe has been tweeting examples of a method for adding an interesting weathered finish on a model by hand-painting a brightly-colored undercoat with lacquer paints before applying the main colors on top. I’ve attempted to emulate this for airbrush.

Why paint a multicolored basecoat in the first place? Aside from adding visual interest, it can also make your model look more lifelike. Observe any vehicle that’s been out and operating for a long period of time, and you’ll notice some slight discolorations. This happens through a variety of reasons: exposure to the elements, replacement of parts, being composed of many different materials painted in a single color, poor maintenance, etc. Here’s an example, a Hellenic Air Force F-16 photographed by George Karavantos:

Modelers use a number of techniques to match this real-life wear and tear. The most common method involves pre-shading and adding weathering effects on top. Pre-shading however, as explained in Doog’s Black Basing Tutorial, relies heavily on tracing over panel lines while simultaneously losing a lot of the work you put into those lines once you go over it with your base colors. Perhaps because of all the work that it requires, it often gives a finish that feels slightly too intentional or controlled to look natural. 

A more realistic alternative to pre-shading is black-basing, which involves misting randomized patterns of the base color in several thin layers on top of a black primer to get a more natural worn finish. This multicolor basecoat does it one better, utilizing the same basic principles, but adding more interest by relying on bright, primary colors as a basecoat to make the final colors pop.

Let’s begin by choosing an easy model to demonstrate this on. Ideally, it should be a kit with a lot of surface area, though as you practice more, you’ll be able to master this on smaller and smaller models.  For this tutorial, I picked the HGUC 1/144 FD-03 Gustav Karl, as it is huge with a lot of flat surfaces. After doing proper preparation such as sanding down nubs and removing seamlines, we can start painting!

Left: straight build. Right: with black primer applied.

For this paint job, I’m using a KK Moon Professional Double Action Pistol Trigger Airbrush with a 0.3 nozzle. Another similar option I’d recommend is Tamiya’s HG Double Action Trigger Type Airbrush.

First, prime the model kit with a black primer. Black immediately solves the problem of adding shading in areas we may normally be unable to reach once we begin fully painting the kit—with this as the base, the corners that would naturally be darkest will already have a black undercoat. That’s why it’s important to get the black primer on every accessible surface, not just the one we intend to paint—even a bit of bare plastic showing through will break the whole feel that we’re going for. 

Here, I primed the model with Gaia Surfacer Evo Black, as I find it to have really nice coverage even when thinned down to a 1:1 ratio of primer to thinner (I’m in the Philippines so I used Anzahl Urethane Thinner, but Mr. Color Thinner or Leveling Thinner would work well for North American modelers). I recommend this ratio of paint to thinner in order to achieve an almost milk-like consistency that covers a lot of surface area without clogging up the paint nozzle. It also dries flat and level in seconds so you don’t have to worry about smearing.

Once we get the model good and covered in black primer, and check for any areas we might have missed, we can proceed with the next step: the multicolor basecoat itself. This will definitely look weird to a lot of modelers, and definitely not “realistic” yet, but just keep going! Add different layers of colors in random cloud patterns while adjusting your airbrush to spray at its narrowest settings. Spraying in a circular motion helps with this step to ensure good coverage. A 1:1 ratio of thinner to paint isn’t really recommended for this step, as we will want this layer to still be slightly visible once we add the final colors on top.

For this model, I painted the undercoat with just three Armored Komodo Basic Colors: Teal, Desert Sand, and Barium Red. That was enough to give me plenty of tonal variation.  You’ll notice that I skipped applying the same colors to the joints and hand parts, as I’ll be painting those in Gunmetal. The logic behind this step is that we want to introduce tonal shifts on a single color, which can represent exposure to the elements and will help enhance any weathering effects we’ll add later on.

As you cover the whole model in this multicolor basecoat, start thinking about how it’s going to affect the final layer of paint. For example, you can see that I’ve added more red to areas that will eventually be red-orange, just to help make the final colors more vibrant. Meanwhile, there are other parts of the model where I’ve omitted adding red entirely to simulate panels made out of different materials than the other parts surrounding it. Doing this is a fun way of thinking ahead and helping yourself out for when you add extra layers of weathering on top of the model.

The third step is covering your previous layer in the intended final colors. For this example, I used Mr. Color 314, “Blue FS35622”, Armored Komodo Low-Vis Gray, Jumpwind Neocolors Red-orange, and Mr. Color 61 Burnt Iron. In this step, we’re spraying once again in a 1:1 paint to thinner coat, with multiple layers to make sure we don’t completely cover our basecoat. Remember: it’s better to spray too lightly and have to airbrush another layer than it is to spray too heavily and conceal all your hard work on the multicolored basecoat! As you paint, you’ll want to gradually build up the color until only the faintest traces of the previous multicolor layer shows through, giving you nice color shifts.

Left: assembled with multicolor basecoat. Right: assembled with paint layer on top.

Here’s my model after I painted the top layer of paint and reassembled it. You can already observe how the parts feature lots of variation thanks to the multicolored basecoat. This is especially noticeable in the largest, flattest pieces, like the lower legs or on the front skirts, where it’s not all a single shade but very cloudy looking. It simulates a discolored surface for a final weathered finish, but you’ll notice that it has the added effect of breaking up a previously boring block of color by adding some different hues.

If you’re happy with the look you can stop here and proceed with the next stage of your build like the detailing and weathering stage. However, if you want to increase the visibility of your tonal shifts, then there is an optional fourth step that you can try out: by lightly brushing some 99% isopropyl alcohol on your paint job in quick, careful jabs, you can re-activate the top layer of paint and subtly blend it in with your previous multi-color layer to define the shifts in color more. Feel free to do as many passes as needed until you achieve your desired effect.

A brushing of isopropyl alcohol helps the basecoat shine through.

You’ll also notice that your top colors will have a bit of a fade and a noticeable flat texture, something that’s beneficial for you if you intend to add weathering to your model. 

In the final image, I added an additional weathering layer with Armored Komodo Water Based Acrylics (Dark Gray, White) and Vallejo Mecha Color (Chipping Brown). It’s enhanced by a filtering and streaking layer I achieved with a Gundam Real Touch Marker (Brown, Gray 1) and some light dusting with Armored Komodo Weathering Pigments (Dark Earth, Light Dust). I also sprayed some black primer thinned heavily to add some soot/carbon burns to the verniers and surrounding areas to make them look recently fired.

Whether you intend to do the bonus step or not, you’ll end up with a nicely painted model to which you can add your finishing touches. It will definitely make for a more visually interesting weathered finish.

Miko, AKA Mokiplamo is an avid Gunpla fan from the Philippines. He’s been interested in the hobby since getting his first SD kit back in 1994. You can catch his shenanigans over at his Facebook page.

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