Seedream 4.0: how to write prompts the model actually understands
ByteDance · Updated:
Seedream 4.0 is the baseline image model from ByteDance and the first generation of the family. Text-to-image up to 2K, optimal prompt length 20–80 words. Available via fal.ai and flux-ai.io. Handles simple scenes and standard genres well, but weaker than 4.5 and 5 on complex multi-element scenes and spatial relationships.
Where 4.0 sits in the Seedream line
Seedream 4.0 is the «reliable baseline soldier» of the family. Stable generation, predictable results on simple prompts, support for standard styles, and basic composition understanding. It is the cheapest and fastest version of the line.
What 4.0 cannot do versus 4.5 and 5: weaker on complex-instruction adherence, weaker spatial understanding (proportions, object placement), less detailed in-image text rendering, lower consistency in multi-object scenes.
Key advice: for 4.0, use short simple prompts rather than long complex ones. Where 5 Lite handles a 120-word multi-layered prompt, 4.0 delivers a better result on a 30-word straightforward one.
- Text-to-Image, up to 2K
- Optimal prompt length 20–80 words
- Standard aspect ratios via --ar
- Basic image-to-image (limited)
- Weak rendering of complex in-image text
Prompt structure
Base formula: `[Subject] + [Style] + [Composition] + [Lighting] + [Details]`. As in other Seedream versions, the subject always goes first — hierarchical prioritization is shared across the family.
For 4.0 a simpler structure is recommended than for 4.5/5. Fewer adjectives, more straightforward phrasing, clean separation of levels. Detail overload performs worse than in later versions.
Example: «A young woman with curly hair, portrait photography, soft studio lighting, neutral background, 85mm lens.» — five components, nothing extra. That is the working minimum for 4.0.
What 4.0 does well
Portrait photography — Subject + appearance + portrait photography + lighting + background. On standard portraits 4.0 delivers almost the same quality as 4.5.
Landscapes and scenes — location + landscape photography + lighting + mood. Natural landscapes with golden hour, mountain lakes, forests are a 4.0 strength.
Product photography — product + material + clean background + product photography + studio lighting. Simple white-background product shots come out clean.
Illustration and art — subject + style (watercolor, oil painting) + colors + mood. Stylized illustrations in a single clear style are a 4.0 sweet spot.
Cinematic shots — scene + character + cinematic + dramatic lighting + lens. Basic cinematic frames are accessible, but without complex choreography across multiple objects.
What 4.0 does poorly
Complex in-image text is a 4.0 weak zone. On posters with long titles the model mangles letters, mixes fonts, adds stray characters. If you need quality text rendering, pick 4.5 or 5.
Spatial relationships between objects — 4.0 cannot reliably hold «a cat on the left, a dog on the right, a window between them». Complex multi-element scenes with explicit placement are an anti-pattern.
Long multi-layered prompts — past 100 words and the model loses focus. 80 words of specifics beats 150 of mixed content.
Iterative work on a single composition — 4.0 holds the same scene between generations less consistently. The version is more «lottery-like»: each generation comes out slightly different.
Common mistakes
1. Long multi-layered prompt
Over 100 words in 4.0 is an anti-pattern. The model loses focus and priorities drift. Where 5 Lite tolerates a long detailed prompt, 4.0 prefers 20–80 words. Specifics in short blocks work better than a long description.
2. Complex in-image text
Posters with long titles, infographics with many labels, UI mockups with interface text — a 4.0 weak zone. The model mangles letters and mixes fonts. If you need quality in-image text, switch to 4.5 or 5 Lite. In 4.0 stick to short words in quotes.
3. Complex spatial instructions
«A cat sitting on a chair to the left of a window, with a dog lying on the floor in front of the chair» — 4.0 won't hold those relationships. You'll get a scene with these objects but in random placement. For precise composition, you need 4.5 or 5.
4. Conflicting styles
«Photorealistic cartoon sketch» or «watercolor 3D render» — 4.0 breaks on conflicts faster than 4.5/5. Pick one dominant style and at most one compatible modifier. «Photorealistic with film grain» is fine. «Realistic anime» is not.
5. Negatives in the main text
«No watermark, no text, no extra limbs» in the main 4.0 prompt is read literally — possibly adding a watermark. All bans go into the platform's separate negative_prompt field. When that isn't available, phrase positively: «no cluttered» → «clean background».
Before / after examples
Example 1
Before
woman in an office
After
A young woman with curly brown hair in a beige blazer, working at a wooden desk in a modern office, portrait photography style, soft natural window light from the left, neutral background, 85mm lens, shallow depth of field, --ar 4:5.
Key change: concrete subject (hair, clothing), explicit photo style, explicit lighting and lens. This is a textbook «80-word» prompt that is optimal for 4.0 — not overloaded but containing every key element.
Example 2
Before
mountain landscape at sunset
After
Mountain lake at sunrise, landscape photography, golden hour lighting, snow-capped peaks reflected in calm water, serene atmosphere, wide-angle composition, subtle morning mist, --ar 16:9.
A natural landscape with golden hour is a 4.0 strength. The prompt is deliberately simple and straightforward (about 25 words), with no complex spatial instructions.
Example 3
Before
matte black mug on a white background
After
Matte black ceramic coffee mug on a white background, product photography, soft studio lighting, sharp focus on the mug, clean minimal composition, subtle shadow, --ar 1:1.
A simple e-commerce shot — 4.0's main lane. One object, clean background, explicit style, explicit lighting. No complex details and no multiple objects — the model works fast and stable.
