@lovewin @Tealfuleyes "oil" colored pencils are not at all different from "regular" high quality colored pencils. Brands use it as a marketing distinction. All high quality colour pencils contain waxes and oils in the binder, and there is no logic to how hard, soft, opaque, or transparent pencils are based on whether they're marketed as "oil based" or "wax based". There may be a difference in how well they respond to solvents (OMS, Gamsol, alcohol, oil).