Which retouching technique is used to separate texture from color for skin and other surfaces?

• A. Gaussian blur.
• B. High-pass filter.
• C. Frequency separation.
• D. Local contrast optimization.

Answer: (C)

Separating texture from color lets you fix skin tones and shading without disturbing surface detail, and you can refine texture without changing color. The technique that achieves this uses two built‑in layers: a low‑frequency layer that holds color and tone, and a high‑frequency layer that carries the fine details and texture. In practice, you create the low‑frequency layer by softening a copy of the image to capture overall color; the remaining detail becomes the high‑frequency layer. With this setup, you can smooth color shifts on the low‑frequency layer while preserving or selectively enhancing texture on the high‑frequency layer, or vice versa. This is why frequency separation is the correct method.

Other approaches don’t separate color and texture. A Gaussian blur alone blurs both color and texture, not allowing independent control. A high‑pass filter by itself highlights texture but doesn’t provide a clean split from color, and local contrast optimization focuses on local tonal changes rather than separating these two components.