# ロゴ用 GPT image プロンプト集（Letters）

> **使い方の前提**：GPT image / DALL·E系は**ワードマークの正確な字形再現が苦手**。
> 文字は最終的に実フォント（Söhne / Aktiv Grotesk / Greycliff / Fraunces 等）で組むのが安全です。
> 生成AIは「**ムード・配色・補助シンボルの方向性探索**」に使うのが目的。
> `logo-concepts.svg` の3案に対応。

## 全案共通で必ず入れる制約（ネガティブ含む）

```
Style: flat vector logo, minimal, geometric grid, generous negative space,
monochrome base + a single accent color, crisp edges, professional, timeless.
Background: off-white (#F6F4EF) or pure studio white.
NO gradients on letterforms, NO 3D bevel, NO drop shadow, NO envelope/mail icon,
NO speech bubble, NO neural-network or circuit motif, NO heart, NO globe,
NO generic tech-startup look, NO stock cliché, NO photorealism.
```

---

## 案A —「つなぐ線 / The Connecting Line」

```
A minimalist wordmark logo for a company called "Letters".
Humanist geometric sans-serif, medium-semibold weight, slightly tight letter-spacing.
A single continuous coral line (#D9462F) runs under the whole word as an underscore,
starting from the foot of the "L" and connecting to the end of the final "s",
with the right end tipping gently upward (2-4 degrees) — suggesting growth and forward motion,
NOT an arrow. The letters themselves are plain black (#14110F) on warm off-white.
The line is the only colored element. Calm, intelligent, optimistic.
[+ 全案共通の制約]
```
- バリエーション指示：`make the underline draw from left to right`（モーション検討用に開始/終了状態を2枚）

---

## 案B —「動くドット / The Moving Dot」

```
A minimalist wordmark logo for a company called "Letters".
Low-contrast geometric sans-serif, semibold, true-circle "e/o", on a near-black panel (#101014),
letters in soft white (#F4F1F7). A single small perfect circle dot in violet (#6C63FF)
sits on the baseline right after the final "s" — like a period / a single starting point.
The dot is the only colored element and reads as a separable system token.
Precise, modern, confident, lots of empty space.
[+ 全案共通の制約] ; NO multiple scattered dots, NO particle field, the dot must NOT look like an eye or a face.
```
- バリエーション指示：`provide the dot alone as an app-icon mark on a violet square`（ファビコン/アプリアイコン検討用）
- 事業色替え検討：`dot in teal #00C9A7`, `dot in amber #FFB347` など

---

## 案C —「構造のL / The Structural L」

```
A minimalist wordmark logo for a company called "Letters".
Bold humanist sans-serif, tight spacing, all horizontal/right-angle structure.
The initial "L" is slightly taller than the other letters and acts as a structural pillar.
A short deep-teal (#00A88C) horizontal rule sits at the baseline under "Letter",
echoing a letterhead / envelope flap as pure geometry (no literal envelope).
Letters in near-black (#1A1A1A) on paper white (#FBFAF7). Sturdy, trustworthy, premium.
[+ 全案共通の制約]
```
- 用途検討：`show the logo small with "Inc." set on the same baseline to the right`

---

## 仕上げメモ

- 推奨の初稿2方向：**案A（最も「ワクワク」）** と **案B（システム拡張性◎）**。
- SVG化が最も容易なのは**案B**（ドット＝`<circle>`、文字＝`<path>`、色替えは `fill` 1箇所）。
- 生成画像はあくまで方向性確認用。確定後にプロのタイポ調整（カーニング・オプティカル補正）を行う前提。