Most likely a translation artifact. The different versions of the formula appear to be ballpark starting points that should be 'dialed in' to suit a particular type of film.Can I ask what "styrax" is
Most likely a translation artifact. The different versions of the formula appear to be ballpark starting points that should be 'dialed in' to suit a particular type of film.Can I ask what "styrax" is
I'm also curious what styrax is. According to search engines, it's a balsamic resin obtained from the cut trunks of trees of the Styrax genus.
But I can't be sure that Google Translate simply made a mistake in translating, or rather OCR reading, the Chinese characters.
Perhaps OP could dispel our doubts.
if we can assume that the "styrax" is a mistranslation and is irrelevant to the process then the whole thing looks just too good to be true
| Name | Chinese | Role in Color Developer |
| Styrax (benzoin resin extract) | 安息香树脂 | Coupler solvent, gelatin swelling aid, improves dye formation and reduces uneven development |
ChatGPT:
What is Styrax used in Chinese photographic color film developer?
ChatGPT said:
In Chinese technical literature on color-film processing, the word Styrax (安息香, benzoin resin) refers to a coupler-solvent / gelatin-swelling auxiliary that is added to color negative developer solutions.
Why it is used
Color film developers (e.g., C-41 type) must allow the color-forming couplers inside the emulsion to move and react evenly with the color developing agent (CD-3 or CD-4). To help this, the developer contains certain organic solvents or “development aids.”
Styrax in this context:
- Improves gelatin swelling, so the developer penetrates the emulsion more uniformly.
- Helps dissolve and mobilize dye-forming couplers, improving color formation.
- Reduces uneven development and improves color density and balance.
- Also has a mild anti-oxidation / preservative effect, extending developer life.
Important distinction
This is not the perfume-grade “styrax essential oil.”
In film chemistry, Styrax refers to benzoin resin extract containing benzyl benzoate and related aromatic esters, chosen for its solvent and stabilizing properties.
Summary
Name Chinese Role in Color Developer Styrax (benzoin resin extract) 安息香树脂 Coupler solvent, gelatin swelling aid, improves dye formation and reduces uneven development

| Name on Label | What It Is | Suitable? | Notes |
| Storax (Styrax benzoin / Gum Benzoin / 安息香 ān xī xiāng) | Resin used in perfume & incense | Yes | Most commonly used in Chinese developer formulas. |
| Liquidambar orientalis “Storax” | Similar aromatic resin | Yes | Also acceptable if listed as 自然苏合香. |
| Styrax “Benzoin Siam” or “Benzoin Sumatra” | Perfume-grade resin granules | Best choice | Generally pure and easy to dissolve in alcohol. |
| Source | Type | Link / Info |
| Etsy | Raw benzoin resin granules | Search “benzoin resin Siam” or “storax resin” |
| eBay | Benzoin resin or storax chunks | Many small-batch sellers |
| Perfumer Supply House / MakingCosmetics / Eden Botanicals | High-purity perfumery resin | Good if you want consistency |
| Alibaba / AliExpress | Direct from Chinese resin suppliers | Search: 安息香 原料 or 苏合香 树脂 |

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