Mr. Hobby Paints (GSI Creos)

Text: Josef Blažek

In the last issue of Info Eduard, we took a detailed look at a new product on the market - Mr. Color GGX paints from GSI Creos/Mr. Hobby, which offer exceptional coverage with a significantly lower odor than we’re used to with lacquer paints. However, to fully harness the potential of this new generation of lacquers, it’s important to understand where they fit within the Japanese manufacturer’s extensive product lineup. In today’s article, we’ll therefore focus on the key differences between individual Mr. Hobby products and their compatibility. We’ll take a closer look at the traditional and well-known Mr. Color lacquers (classic synthetic lacquer paints) from the C series and their premium GX variants. At the same time, we’ll compare them with the user-friendly Aqueous Hobby Color acrylics (H series).

The Legendary “C Series”

The basic Mr. Color line (known among modelers as the C Series) embodies an absolute classic and has formed the backbone of many modelers’ kits for decades. The history of these paints is quite long. The roots of this series date back to the 1960s, when interest in plastic model building was growing rapidly in Japan, but there were no paints designed specifically for plastic modelers, so they had to mix everything themselves. The company Gunze Sangyo released a solvent-based acrylic resin paint called Level Color, designed specifically for them. In 1977, these paints were rebranded under the name Mr. Color, which is still used today. From a chemical standpoint, these are so-called lacquers. The pigment is dissolved in a mixture of organic solvents and strong synthetic resins. While this results in a characteristic pungent odor, it also delivers uncompromising properties, characterized primarily by high surface durability and fast drying. A major benefit of the C series is its vast color palette, comprising hundreds of shades, which covers the colors needed by modelers specializing in aircraft and military vehicles. These are primarily shades based on the RLM, Federal Standard, RAF, and IJN standards.

Drying, Durability, and Layering

As already mentioned, a major advantage is the speed of drying. When applying with an airbrush, we can literally say that the paints dry before your eyes. The liquid layer evaporates from the surface within a few seconds after spraying and is touch-dry. Once fully cured, the paint forms an extremely hard surface that is exceptionally resistant to mechanical abrasion. This is a major benefit when handling the model and when using a wide variety of chemical weathering agents. It also handles rough handling with masking tape, the application of decal setting solutions (e.g., Mr. Mark Setter and Mr. Mark Softer), and subsequent weathering using synthetic (enamel) or oil-based washes exceptionally well. Furthermore, the layer is so thin that it does not flood even the finest details, rivets, and engravings on the model. Another point worth mentioning is the ability to sand the paint, which is particularly valuable when correcting mistakes made by the modeler or when debris has become embedded in the surface. In such cases, the paint does not peel off but is gradually and evenly removed by sanding.

The Alchemy of Thinning and Official Additives

Mr. Color base colors (C series) come in bottles in a thick consistency and must be thinned for airbrushing at a ratio of 1:1.5 to 1:3 (or even 1:4) in favor of the thinner. It’s important to note here that there is no single “ultimate” dilution ratio for these paints, because the ideal dilution varies depending on the specific conditions of your work—such as the type of airbrush, nozzle size, and compressor pressure settings—and also depends on the ambient temperature in the room. In general, I recommend aiming for a higher dilution ratio of approximately 1:3 to 1:4. It is best to use genuine Mr. Hobby thinners for dilution. The standard base thinner is Mr. Color Thinner (blue label). Paint dried with this thinner dries very quickly while retaining the core benefits and advantages of Mr. Color paints. However, when spraying from a greater distance, at higher pressure, or at higher temperatures, the paint may dry too quickly—specifically, even while traveling from the spray gun nozzle to the model’s surface—which creates unwanted “speckles” on the model and, in extreme cases, causes the paint to dry on the spray gun needle. In such cases, it is advisable to increase the dilution ratio or use thinners containing additives. A good example is Mr. Color Leveling Thinner (yellow label). Personally, I consider it the most versatile—and therefore the best—choice for working with Mr. Color paints. It is essentially a standard thinner with a drying retarder added. This additive prevents the paint from drying on the spray gun needle and helps the paint, once it hits the model’s surface, to have more time to “spread” perfectly across the surface. Another option for thinning Mr. Color paints is Mr. Rapid Thinner (pink label). This fast-drying thinner is quite specific and is intended primarily for matte paints and metallic paints. It accelerates evaporation, thereby preventing, for example, the heavy pigments in metallic paints from clumping into spots. Another way to further influence the properties of Mr. Color paints is by adding the Mr. Retarder Mild additive. This is a standalone additive (drying retarder) that is added to paint that has already been mixed. In combination with Mr. Color Thinner, we can simulate the properties found in Mr. Color Levelling Thinner or, conversely, slow down drying by using Mr. Color Levelling Thinner—which is very advantageous when spraying extreme details or thin, “snake-like” camouflage patterns. 

Mr. Color GX

The GX paint series represents the next stage in the evolution of Mr. Color paints (C series). The chemical composition of GX remains based on a synthetic lacquer, making it fully compatible with C series paints . The difference lies in the fact that the manufacturer has used a finer and more densely concentrated pigment with a new binding resin. The GX series color palette is intentionally narrower and focuses on basic shades and clear coats. The improved properties are evident in a significant advancement in terms of extreme surface hardness—highly scratch-resistant—and lightning-fast drying, making them ideal, for example, for polishing model cars to a mirror finish. Thinning the paints is similar to that of Mr. Color paints; ideally, use the aforementioned Mr. Color Levelling Thinner, which, thanks to its slower drying time, allows the thick resin to “settle” perfectly on the model’s surface and create a perfectly uniform and smooth coat of paint.

Aqueous Hobby Color (H Series)

While the classic “C” series relied—and continues to rely—on uncompromising chemistry, in the 1980s (with the launch of the H series in 1982), the then-company Gunze Sangyo responded to global demand for safer and less odorous household paints. The result was the introduction of a new line of paints under the brand name Aqueous Hobby Color (referred to as the H Series). From a chemical standpoint, it is a sophisticated hybrid in which pigment and acrylic resin are dissolved in a solution consisting of roughly one-third water and two-thirds isopropyl alcohol. It is the alcohol that plays a key role here, as it reduces surface tension, preventing the paint from forming droplets on a plastic model and allowing it to dry very quickly, all while emitting only a minimal odor.

Aqueous (H) versus Mr. Color (C): How Do They Differ?

Personally, I see two main differences between the two main paint lines. These are primarily differences in their durability and color palette. Let’s first explain the first difference. Mr. Color paints (C series) create an extremely hard and durable surface once dry. Aqueous (H series) is noticeably softer once the paint has dried. It is therefore more susceptible to mechanical abrasion, and if masking tape is used carelessly—especially when removing it—there is a risk of damaging the surface. As for the color palette, while the C series is positioned as the ultimate military and historical palette, the H series focuses on versatility. The palette is thus intentionally about half the size of that of lacquer paints. A potential advantage of the “H” series is that, thanks to their slower drying time, they are easier to work with when painting very fine details.

Thinning H Series Paints

Due to its hybrid nature, diluting the Aqueous series is highly variable, which gives us considerable flexibility in dilution. In my view, the dilution process is very similar to that of the C series, but in my experience, a lower dilution ratio of 1:2 in favor of the thinner is usually sufficient. If we stick exclusively to the original thinners, the H Series paints have their own Aqueous Thinner (blue-green label). This thinner contains a precise ratio of alcohol to water, which gives the paint ideal properties for airbrushing. The result is a beautiful, semi-matte to glossy finish and consistent drying of the paint after application. The paints can also be thinned with the thinner listed among the thinners for Mr. Color C paints, specifically the Mr. Color Leveling Thinner (yellow label). Although this is a thinner designed for the C series, the alcohol component in the Aqueous paint blends perfectly with it. The lacquer thinner “removes” the paint’s water-based character. The paint dries noticeably less on the spray gun needle and blends into a perfectly smooth surface on the model. After curing, it takes on properties closer to those of the C series paints.

Conclusion

Both Mr. Hobby’s C and H paint series offer top-tier quality in their respective segments. The final choice therefore depends primarily on individual preference for mechanical durability and drying speed (advantages of the C series) or ease of use and lower odor (H series). Both series can be combined in multiple layers on a model when applied according to the instructions, providing modelers with a high degree of flexibility. To provide a better overview of their use and combination, I have prepared a table of key characteristics comparing the GGX, GX, C, and H series.