# Colourway guide

## How the Skill keeps the product locked

Every colourway is a separate edit of the same photo, with the same prompt and only the colour changed. The prompt names exactly which parts change (`--recolour`) and says that everything else, including the camera angle, framing, lighting, shadow and background, stays identical. Start from a clean, well-lit photo on a plain background (the Skill `studio-product-shot` makes one). Busy backgrounds drift between runs and make the sheet look inconsistent.

## Naming the parts that change

Be specific. "The three side panels and the whole midsole" works. "The accents" does not. For each product, list the parts that change and the parts that must not (laces, label, logo, hardware, stitching colour, sole tread).

| Product | Typical recolourable parts | Lock |
|---|---|---|
| Sneakers | Panels, overlays, midsole, laces | Mesh texture, perforations, logo, tread |
| Bags | Body leather or fabric, strap | Hardware, stitching, logo emboss |
| Bottles, tubes | Cap, body, label background | Label text and layout, shape |
| Packaging pouches | Pouch film or paper, label band | Wordmark, logo, barcode areas |
| Apparel | Fabric body, trims | Print, seams, labels |
| Electronics | Shell, buttons, cable | Ports, screen, text |

## Choosing colours

- Give a name and a hex code, `Navy=#1B2A4A`. The hex is what the model matches; the name is what appears on the sheet.
- Four to six colours is a normal range. Spread them across the wheel plus one neutral (black, charcoal or off-white).
- Check dark colours against the finish. Near-black needs a "matte near-black charcoal" in the prompt, or the model flattens detail.
- Pastel and neon colours shift most. Always compare against the hex.

## Materials

| Material | What happens | Prompt note |
|---|---|---|
| Matte leather, rubber, plastic | Easiest | None |
| Glossy or patent | Highlights may go flat or change shape | Add "keep the same glossy highlights" |
| Metallic and chrome | The reflected environment must stay; colour shifts to tint | Use tint words: "gold-tinted metal". Expect more retries |
| Fabric with a weave or print | Print may be redrawn | Lock the print explicitly; if the print must change colour, say which print colour |
| Transparent or glass | Tint leaks to the background | Name "tinted glass, background stays white" |
| Multi-colour products | Wrong parts change | Recolour one named group per run |

## Reading the result

Put the original beside each colourway and check, in order:

1. Parts that were meant to stay (laces, label, hardware, tread) look the same.
2. Only the named parts changed colour.
3. Shading and shadow match the original: same light, same soft shadow.
4. Framing, scale and position match across every colourway. If one is smaller or shifted, re-run that one only.
5. Label and logo text unchanged, letter for letter.
6. The colour matches the hex code to the eye.

Note that the model re-renders the product. Fine details (stitch count, the exact lace pattern, texture grain) can differ slightly from the photo. If the person needs the exact photographed pixels, tell them, and use a manual retouch for those colours.

## Failure modes

| Symptom | Fix |
|---|---|
| Whites tinted by the new colour | Add "the white parts stay pure white and untinted" |
| Label or logo changed | Name it as locked; if it repeats, use the fallback model |
| Shape drifts between colourways | Same prompt, same input photo every time. Never feed one colourway into the next |
| Wrong parts recoloured | Describe the parts by position ("the heel panel behind the ankle") |
| Colour too dull or too bright | Re-state the hex and add "flat colour, no gradient" |
| Product moved or rescaled | Add "same position, same scale as the reference"; re-run that one |