/sketch

Prompt Patterns Reference

Purpose: Read this when Sketch needs canonical prompt architecture, prompt-quality thresholds, JP -> EN translation rules, policy-safe rewriting, or v1.50+ prompt controls.

Contents

• Prompt architecture
• Style preset library
• Domain templates
• JP -> EN translation rules
• Policy-safe prompting
• Quality checklist
• Negative patterns
• SDK v1.50+ controls

Prompt Architecture

Build prompts in this order:

[Subject] + [Style] + [Composition] + [Technical]

Construction rules:

1. subject first
2. style immediately after the subject
3. composition before technical polish
4. technical keywords last

Style Preset Library

Photorealistic

photorealistic, natural lighting, detailed textures, DSLR quality, sharp focus, high dynamic range

Digital Illustration

digital illustration, clean lines, vibrant colors, flat design, modern graphic style

3D Render

3D render, isometric view, clean geometry, soft shadows, ambient occlusion, PBR

Watercolor

watercolor painting, soft edges, translucent layers, paper texture, bleeding colors

Abstract

abstract composition, geometric shapes, bold color palette, minimalist design, conceptual art

Additional styles:

• oil painting
• anime/manga
• vintage/retro
• cyberpunk
• art nouveau
• minimalist

Domain Templates

Marketing / hero image

[Product/Scene], professional commercial photography, hero image composition, brand-appropriate lighting

Recommended ratios:

• 16:9
• 21:9

Product photography

[Product] on [surface/background], studio product photography, soft box lighting, clean minimal composition

Recommended ratios:

• 1:1
• 4:3

UI / UX assets

[UI element/icon/illustration], flat design, UI-ready, consistent line weight, transparent-ready

Recommended ratio:

• 1:1

Documentation / technical

[Concept visualization], clean infographic style, explanatory illustration, clear visual hierarchy

Recommended ratios:

• 16:9
• 4:3

Social media

JP -> EN Translation Rules

Rules:

1. restore omitted subjects
2. replace vague adjectives with concrete English keywords
3. expand mood words into recognizable visual descriptors
4. keep technical terms in English

Common mappings:

Keep this must-keep example:

Input (日本語):

やわらかい光のなかで、木のテーブルの上にコーヒーとノートパソコンがある、おしゃれなワークスペース

Output (English prompt):

A stylish modern workspace with a laptop and coffee cup on a wooden table, soft diffused natural lighting, cozy atmosphere, shallow depth of field, warm tones, lifestyle photography, 8K detail

Policy-Safe Prompting

Safe patterns:

• use generic people descriptions instead of named real people
• use generic workplaces instead of branded offices
• use descriptive traits instead of copyrighted character names

Fallback sequence when a prompt is risky:

1. remove sensitive keywords
2. replace specific references with generic descriptions
3. reframe with positive keywords
4. simplify the prompt
5. suggest an alternative concept if still blocked

Prompt Quality Checklist

• subject is specific
• style keywords do not conflict
• aspect ratio matches the use case
• no copyrighted character or brand reference unless explicitly required
• person-generation policy is checked
• prompt is in English
• technical keywords are present
• prompt length stays in the 50-200 word range

Negative Patterns

Style conflicts

Prompt length

Ineffective patterns

Quality-keyword rule:

• choose 3-5 strong quality keywords, not a long stack

SDK v1.50+ Controls

If v1.50+ is available, use:

image_generation_config=types.ImageGenerationConfig(
    aspect_ratio="16:9",
    person_generation="DONT_ALLOW",
)

Available parameters:

Version guidance:

• v1.38+: control ratio and people via the prompt
• v1.50+: prefer parameters for ratio and person generation, and keep the prompt focused on subject and style