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Dot Filtering With Oil Paints

By Lance Masunaga

Dot filtering has become a popular technique used to impart a realistic weathered appearance to models. The slow drying time of oil paints allows the modeler to work in elaborate effects that would not be possible with acrylic or enamel paints. However, dot filtering requires a leap of faith on the modeler’s part, as the steps involved can look quite alarming.

The most important first step in dot filtering is to provide a stable base coat of paint. The thinners used (paint thinner, turpentine, or lacquer thinner) will affect enamel based paints, so a protective clear coat must be provided. Gunze or Tamiya Clear Gloss or Semi-Gloss from the spray can will provide a near bullet-proof coating, and will dry quickly. A model painted with acrylics will not require any preparation. The model is then given the usual detail washes and drybrushing per the individual’s taste.

The next step is to get some oil paints. Although they can be pricey, remember that a little will go a very long way, and that when properly stored, can last a lifetime. The colors used will vary according to the model’s base color and personal tastes, but the basics will include various shades of brown. Black and white will also come in handy to fine tune the other colors. Primary colors like red, yellow, and blue can also be used for dot filtering, but the best advice it to try it out and see which colors give the best results.

A sheet of plastic with embossed rivets was base coated with Tamiya silver spray paint.

Citadel acrylic Rust Brown Ink Wash and Black Ink Wash were applied with a brush.

The sheet was then drybrushed with acrylic Vallejo Liquid Silver.

Citadel acrylic Gryphonne Sepia and Skaven Brown were applied as washes to create a weathered appearance. The washes must be kept from pooling to avoid water stain marks.

The washes are allowed to dry completely before starting the dot filtering process

Dot filtering begins with applications of fine dots of random colors. The colors used were Raw Umber, Burnt Sienna, Crimson Alizarin, Venetian Red, and Yellow Ochre. At this point the model will look ruined, but the magic show is about to begin!

The oil paint is then streaked and blended using lacquer thinner. The brush must be frequently cleaned to prevent the colors from becoming uniform.

Done! The sheet now looks rusty, greasy, and grungy - perfect for something like Games Workshop’s Ork Stompa!

The hardest part about doing dot filtering is getting the courage to try it out. Once the process is started, fear will give way to confidence, and the model will take on a whole new look. It is noteworthy to mention that the Ork Stompa shown on the right was my first try at the technique!

This Games Workshop Ork Stompa was weathered using the process described in this article.

The combination of drybrushing, acrylic washes, and oil paint dot filtering creates a deep layering of colors which enhance the molded in detail of the model.