Here's a useful tutorial from Martin Kováč, enjoy!
Creating subtle color variations during the first stages of a paintjob is very enjoyable process. Some of these effects, such as Filters or Fading, might not be very evident after the model is finished, but we would definitely notice their absence if we decided to proceed without them.
In the first photo we have our model with some basic Color Modulation applied. Although Modulation enhances the shapes of our model, it’s just a first step in the painting process and the model lacks definition.
Let’s change that by giving the model a general wash. Mix a dark color which will match the basecoat of your model. In the case of this Maus we are using a dark maroon wash. Consistency of this wash should be around 80% Enamel Thinner and 20% paint. Wilder Oil Paints dry to a matt finish which will work in our advantage during this step.
Apply the wash using a large round brush over the whole model. Working in smaller sections allows us better control of the effect. Note how the armor texture on the side plate starts to become more evident.
Oil paints are also useful for creating our own filters. Consistency of the filter can vary depending on the effect we need to achieve. If we are trying to subtly blend the different camouflage colors together, the consistency should be around 90% Enamel Thinner and 10% paint. If we want to radically distinguish different panels as in this example, the filter should be more opaque. This will save us a lot of time as one layer might be just enough for our purposes.
You can apply the filter in a similar manner like the general wash, just spread it more evenly over the surface and avoid any paint accumulations around details. Otherwise you will end up with another layer of a wash. Matt surfaces accept filters more easily because of their microscopic texture.
After the previous effects had a few hours to dry, we can apply a more controlled pin wash around weld seams and other crevices. This gives details more definition and our model will get a sharper look. In this case we are using the Deep Shadow Wash from Nitroline, which has perfect consistency for this task.
Once again, try and work in smaller sections at a time as this will give you more control over the effect. After a few minutes you can clean the excess wash with a brush moistened in Enamel Thinner.
Oil paints are also the #1 choice for adding and blending small dots of different colors over the model. This technique is also known as Fading because it gives our model a nice faded appearance. As always, work in smaller sections for more control and apply the paints directly from the tube without any thinner. The choice of colors is up to you, but if you are applying them over Color Modulation, try to apply dark tones over shadowed areas to enhance the 3D aspect of your paintjob. Same applies for lighter tones and highlights.
Blend the oil dots using a flat brush moistened in Enamel Thinner. Don’t apply too much of the thinner, otherwise you’ll remove too much of the paint, making the resulting effect not apparent. You can apply oil paints in a more controlled manner around the edges of different armor plates to create subtle contrast between them.
In this last photo we can see the result of our work with some basic painting techniques. Apart from the white markings on the hull, the model has much more contrast, all details are sharply visible and different panels and armor plates are visually separated from each other, making the model much more interesting to look at.