When Hermès approached us for their Spring 2025 silk collection, the brief was deceptively simple: “Make the fabric feel alive.”

Silk is one of the hardest materials to render accurately. It has specular highlights, subsurface scattering, anisotropic reflection, and micro-creases that determine how light wraps around folds. Getting one of those right is hard. Getting all four in the same image — and making it look effortless — is what separates a prompt engineer from someone who types “make it look luxurious” into a text box.

The prompt architecture

For this campaign, we built a 3-layer prompt system:

Layer 1 — Material definition. “Matte crepe silk with a 0.3mm thread density. The weave is diagonal at 22°. Light hits at incidence angle 38° producing subsurface scatter with a falloff exponent of 2.2. The fabric has a slight peach-skin texture visible only in the shadow areas — 2% opacity grain.”

Layer 2 — Lighting specification. “Single key light 5K at 60° elevation, 45° camera-left. The rim is a 1-stop-underexposed fill bouncing off a 2m×2m diffusion scrim at 90° camera-right. The background falls into zero-lux darkness at a gradient of 1.3 stops per meter from the product.”

Layer 3 — Post-processing instructions. “Apply a 3% warm-tone split at the midtones. Lift the shadows by 0.2 stops. The highlight rolloff should follow the Arri LogC curve with a 0.8 contrast ratio.”

The result: 12 images that Hermès legal approved for global use after a single round of revisions.

Why this matters

No luxury brand will accept “close enough” for a global campaign. They need the silk to look specifically like Hermès silk — not generic satin, not polyester. That specificity is what prompt engineering delivers. It’s not typing a wish into a box. It’s coding light.