# Hard-Edge Painting (ハードエッジ・ペインティング)

> Painting that keeps every boundary perfectly sharp and builds the picture out of flat planes of colour alone. Brushwork and gradation are excluded, so the edge of a plane becomes the only event. The precise edge obtained by masking is the direct ancestor of later flat design and vector work.

- IndexStyle No.489 — https://indexstyle.org/styles/hard-edge
- Kind: Style · Family: Geometric Abstraction · Era: 1959–1970s
- Mood: Trust, Technology, Calm
- Color cues: #e9e6dd / #67635d / #171615 (cues taken from reference works, not a fixed palette)

## Defining characteristics

- Perfectly sharp boundaries between planes
- Flat colour with no gradation
- A few large planes only
- The shape itself determining the support

## Best used for

- Identity and signage systems that must survive at any scale in flat colour, with no gradient or shadow left to reproduce badly
- Interface and icon work built on hard vector silhouettes, where legibility is purely a function of edge and area

## Research method

This entry records a historical style; derive the treatment from its sources rather than a fixed recipe:

- A geometric sans in a single weight, treated as a flat plane of its own and aligned to the same edges as the colour.
- Two to four fields dividing the format, with the division placed off any obvious fraction so the areas stay in tension.
- Flat, opaque, unmodulated colour with the edge cut mechanically, showing neither overlap nor a light halo.

## What to avoid

Softening one edge for depth: a single feathered boundary reintroduces illusionistic space, and the picture reverts to being a picture of something.

## Application checklist

Before calling a piece an application of this style, check it against the defining characteristics:

- [ ] Perfectly sharp boundaries between planes
- [ ] Flat colour with no gradation
- [ ] A few large planes only
- [ ] The shape itself determining the support
- [ ] At least one reference work below has been studied directly
- [ ] The caution above ("What to avoid") has been addressed

## Related styles

- **Color Field Painting (カラーフィールド・ペインティング)** — Builds spaces of color that envelop the viewer — large continuous fields, soaked edges, few forms, long perceptual time. → https://indexstyle.org/styles/color-field-painting
- **Flat Design / Vector Minimalism (フラットデザイン / ベクターミニマリズム)** — Reduces information to plain planes and color, portable across screens and media. → https://indexstyle.org/styles/flat-design

## Further study

- Jules Langsner's coining of the term in 1959
- Its development into the shaped canvas
- The psychological effect of plane and edge

## Reference works

- Ellsworth Kelly《赤・黄・青・白・黒》— Wikimedia Commons / Public domain — https://commons.wikimedia.org/wiki/File:Ellsworth%20Kelly%20-%20Red%20Yellow%20Blue%20White%20and%20Black%20-%20Google%20Art%20Project.jpg
- Ellsworth Kelly《Antibes》1950, SFMOMA — Wikimedia Commons / CC BY-SA 4.0 — https://commons.wikimedia.org/wiki/File:Antibes%2C%201950%2C%20Ellsworth%20Kelly%2C%20no%20San%20Francisco%20Museum%20of%20Modern%20Art%2C%20SFMOMA%2028.jpg
- Ellsworth Kelly《Chuan-Shu》1949, SFMOMA — Wikimedia Commons / CC BY-SA 4.0 — https://commons.wikimedia.org/wiki/File:Chuan-Shu%2C%201949%2C%20Ellsworth%20Kelly%2C%20no%20San%20Francisco%20Museum%20of%20Modern%20Art%2C%20SFMOMA%2026.jpg

## Source of record

- Tate — Art Terms: Hard-Edge Painting — https://www.tate.org.uk/art/art-terms/h/hard-edge-painting

## Machine surfaces

- JSON: https://indexstyle.org/api/styles/hard-edge
- Image-generation prompt (legally clean): https://indexstyle.org/styles/hard-edge/prompt.txt
- MCP: https://indexstyle.org/mcp (tools: search_styles, get_style, compose_styles; prompts: image-prompt, apply-style)

## 日本語

境界を完全に鋭く保ち、平坦な色面だけで画面を構成する絵画。筆致も階調も排し、色面の縁が唯一の出来事になる。マスキングによる正確な縁は、以後のフラットデザインやベクター表現の直接の祖先である。

特徴: 完全に鋭い色面の境界／階調のない平坦な塗り／限られた大きな色面／形状そのものが支持体を決める
注意: 表面的な記号へ還元せず、時代・地域・技術・制作主体の文脈を確認する。