Nano Banana Prompt Playbook

Updated: 2026-08-21. Model capability and UI wording follow Gemini and the image generation docs for that day.

Introduction

For “Nano Banana prompts” and “Gemini image prompts,” quality gaps rarely come from adjective piles. They come from writing prompts as checkable art briefs: use, canvas, subject, framing, light, materials, on-image text, and bans. This guide gives a fixed structure, three paste-ready templates, and stable patterns for edits and type—so fewer “looks okay but can’t ship” rounds.

What this guide solves

• Turn empty prompts into reusable image specs with a seven-part structure
• Copy-ready templates for product stills, poster/social covers, and local edits
• Higher success for short on-image copy—and when to switch to post layout
• Negatives and single-variable iteration to control style drift

Write prompts as art briefs

Suggested order (you can compress; don’t scramble the logic):

1. Use & canvas: hero / PDP / poster; aspect and rough resolution tier
2. Subject: what, count, pose, must-keep brand or product traits
3. Framing & camera: center / rule of thirds, margins, angle and focal feel
4. Light & palette: key direction, contrast, brand or banned colors
5. Material & style: photo / 3D / illustration / flat infographic
6. On-image text: exact short lines; language and placement
7. Bans: watermarks, extra limbs, clutter, unauthorized logos

Empty: “draw a nice café” → hard to accept.
Spec: “16:9 blog hero; latte with latte art slightly left; shallow 50mm; window light; warm cream + deep green; photo-real product; no type; no logos or watermarks” → iterable.

Three copyable templates

Product still life

Use: ecommerce main image, 1:1.
Subject: [full product name and material], fully visible, slight 3/4 angle.
Background: clean [color] seamless, soft contact shadow on the ground.
Light: soft top-side key; highlights not blown.
Style: commercial product photography, real material texture.
Text: none.
Ban: hands, damaged packaging, watermarks, extra props stealing focus.

Poster / social cover

Use: social cover, 16:9.
Theme: [one-sentence theme].
Framing: large left margin for title; subject on the right.
Subject: [person or object], mood [keywords].
Style: [flat illustration / editorial photo / 3D render].
On-image text (must be exact): "[short title]", English, bold, top-left safe zone.
Palette: [primary] + [secondary].
Ban: legal microcopy, QR codes, extra logos.

Local edit (multi-turn)

Keep the previous camera, pose, palette, and background.
Change only: [single variable, e.g. swap the cup for a closed notebook].
Do not redraw the whole frame; do not change subject identity or light direction.

One variable per round—or you can’t tell which sentence broke the image. Full beginner flow: Getting started. Tier choice: Nano Banana 2 and 2 Lite.

Steady on-image text

• Keep copy short; put exact wording in quotes.
• State language, case, rough hierarchy, and placement (top-left / bottom safe zone).
• Zero-error spelling or complex trademark glyphs: generate blank, then type in design tools.
• Legal fine print, dense tables, QR codes: don’t expect one perfect generate—prefer post overlay.

Negatives and diagnosis

Symptom	Likely cause	Next round
Style jumps	Too many conflicting adjectives	Cut to 1 main style + 1 material ref
Subject warps	Weak constraints or too many changes	Lock camera/pose; change one object
Soft/garbled text	Too much or too small type	Shorten copy or blank + post layout
Brand off	Missing refs or must-keep traits	Upload refs; say “keep pack geometry and color blocks”
Dirty background	No bans	“Clean background, no clutter, no watermark”

Batch drafts on Lite to control cost; finalize on 2 or Pro—pipeline in the 2 Lite guide. Scene cards: Styles & scenes.

Completion checklist

• Prompt includes use, aspect, subject, light, style, bans
• On-image text proofed character-by-character (or post layout chosen)
• This round changed one variable only
• Reference rights confirmed
• Limbs and artifacts checked at thumbnail and target size

Quick access

• Official experience: Gemini
• Dev/debug: Google AI Studio
• China-friendly third-party (not Google): Nano Banana 2

Third-party accounts, logs, and routing may differ—don’t upload sensitive assets. More paths: China access.

FAQ

Are longer prompts always better?

No. Long, conflicting adjectives reduce control. Hard constraints first, style second—better than twenty near-synonyms.

Should I write prompts in English only?

English works well for many photo terms; mix languages if your entry is steadier that way. Judge by same-subject A/B on your current entry—not ideology.

Do negatives need a separate field?

Some UIs have an “avoid” box; otherwise put bans at the end of the same block. The point is checkable: no watermark, no extra fingers, no warped logos.

Same prompt, different every time—normal?

Yes. For reproducibility, lock tier, aspect, refs, and core sentences, and version successful prompts. API scenarios: API guide.

Official resources

• Gemini
• Google AI Studio
• Gemini API image generation

Further reading

• Nano Banana guides hub
• Getting started
• Styles & scenes
• In-site GPT Image 2 workflow contrast

Summary

Nano Banana prompting is specification: use and canvas first, checkable subject and framing, short accurate text, hard bans, one variable per iteration. Run templates until they stick, then turn them into team style cards; for batch and product wiring, move to API and tier routing next.