[George]

Ann,

For oil paintings, it is generally best to avoid commercial paint markers—such as Krylon or Molotow markers—when the goal is long-term permanence. Most of these products are formulated with acrylic resins, solvent-borne industrial paints, or alkyd systems designed for craft, signage, or mixed-media work. While they may perform well on many surfaces, their aging behavior in a traditional oil-painting structure is largely undocumented. The primary concerns are long-term adhesion, solvent interaction with the oil layers, and the possibility that the marker film may age differently than the surrounding oil paint.

If the halo outline will remain visible and will not be painted over, the safest approach is to apply it using oil paint itself, adjusted to flow smoothly enough for precise line work.

A few practical approaches that artists commonly use for this type of detail work:

1. Use a liner or rigger brush with fluid oil paint
Thin the paint slightly with a small amount of linseed oil or stand oil, and if needed a minimal amount of mineral spirits. The paint should flow easily but still retain sufficient body so the line remains crisp. A liner brush allows very controlled, continuous lines.

2. Use an empty marker body (with caution)
In theory, an empty marker such as the Molotow body you linked could be filled with oil paint, but oil paint tends to be quite thick and may not exit the felt nib, which can quickly clog the mechanism. These markers were designed primarily for acrylic systems. You would likely need a paint mixture with a relatively low viscosity and a stable suspension, which is difficult to achieve with traditional oil paint alone.

For icon work specifically, many painters instead use mahl sticks, ruling pens, or striping brushes, which allow very steady, repeatable lines without introducing unfamiliar materials into the painting.

One additional practical suggestion: if uniform width is critical, you may find it helpful to lightly guide the line with drafting tape or a compass guide and then paint the line freehand with a liner brush.

In short, for longevity and compatibility with the rest of the painting, it is best to stay within the oil-paint system rather than introducing commercial paint markers.

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