Composites pixel-perfect UI onto device photos and renders - screen whites about 1 stop below the key highlights so displays never clip, a diagonal gradient reflection at 3-8 percent opacity with a 45-degree cut edge laid over the UI, device corner-radius masking, slight luminance falloff toward screen edges, and plausible fixture data consistent across every shot of a campaign. Use when someone asks "how do I put a screenshot onto a device photo realistically", "the screen in our product shot looks fake", "composite our app UI onto the phone render", "how bright should the screen be in a device photo". Do NOT use to design the screenshot content or its marketing framing - use marketing-screenshot-craft instead; for the shot around the device, use studio-lighting-design and hero-shot-composition.
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name: screen-compositing-craft
description: Composites pixel-perfect UI onto device photos and renders - screen whites about 1 stop below the key highlights so displays never clip, a diagonal gradient reflection at 3-8 percent opacity with a 45-degree cut edge laid over the UI, device corner-radius masking, slight luminance falloff toward screen edges, and plausible fixture data consistent across every shot of a campaign. Use when someone asks "how do I put a screenshot onto a device photo realistically", "the screen in our product shot looks fake", "composite our app UI onto the phone render", "how bright should the screen be in a device photo". Do NOT use to design the screenshot content or its marketing framing - use marketing-screenshot-craft instead; for the shot around the device, use studio-lighting-design and hero-shot-composition.
---
# screen-compositing-craft
Never photograph or render UI in camera as the final frame - real screens moire, clip, and color-shift, and the composite is how every flagship device image is actually made. The screen is the one part of the frame every viewer inspects, so it fails loudest: a blown white rectangle reads as a glowing sticker, and one impossible screen poisons every true claim around it. This skill produces the layered composite spec that makes the glass honest - brightness, reflection, mask, and data - so the device reads as a lit display living in that scene.
## Operating procedure
Run the steps in order: plate first, geometry second, light third, content last. The composite's brightness and reflection are relative to the plate - screen luminance cannot be set until the key-highlight value is known, and the reflection cannot be laid until the scene's key direction is on record.
### Step 1: Elicit the plate, the UI, and the charter
Gather exactly these inputs before touching a layer. If any input is a guess, label it a guess and move on.
1. **Charter**: the client's brand charter for the on-screen tokens (accent, canvas pair, type weights, CTA geometry). Paste the charter block if one exists. If the client has a charter but the foundations pack is not installed, elicit the needed values directly and label them provisional. If no charter exists at all, halt and route to premium-design-foundations - never substitute worked-example values.
2. **Plate**: the device photo or render, with its key-highlight luminance value sampled and recorded - a picker reading from the brightest chassis highlight.
3. **Geometry**: the device's exact corner radius and screen dimensions, taken from the device spec, never eyeballed.
4. **UI frame**: a pixel-perfect export from the shipping build. If the supplied frame is a design mockup rather than a build capture, flag it - the honesty contract requires product truth.
5. **Fixture data**: the campaign fixture dataset defined in marketing-screenshot-craft, its sole owner. If that pack is not installed, ask for the fixture records the campaign already uses and reuse them verbatim - never create a second set.
6. **Key direction**: the scene's key direction from the rig plan (studio-lighting-design), which the reflection must agree with.
### Step 2: Place the UI on a dark screen