PSD ファイルについて
PSD (Adobe Photoshop Document · 画像フォーマット)
Adobe Photoshop Document（.psd）は、専門的なワークフローやデータ交換・アーカイブで広く利用されているファイル形式です。KaijuConverterで高速に変換できます。
カテゴリ
Raster & Vector Images
拡張子
.psd
MIMEタイプ
image/vnd.adobe.photoshop, application/x-photoshop
対応ロール
PSD が誕生した
背景と歴史。
PSD — Photoshop Document — was born in 1987 when Thomas Knoll, a computer science student at the University of Michigan, wrote a display program called Display for his Mac Plus. His brother John, working at Industrial Light & Magic on Star Wars effects, convinced him to expand it into a photo editor. They sold the software — renamed Photoshop — to Adobe in 1988, and Photoshop 1.0 shipped in February 1990 on Macintosh.
PSD is the format's native save file: layers, masks, adjustments, smart objects, text, effects — all preserved in a single binary blob. The format has evolved through Photoshop versions without breaking backward compatibility: a PSD made in 1990 still opens in Photoshop 2026. It also became the lingua franca between designers and developers — every agency, studio, and enterprise graphics pipeline has at some point standardized on PSD hand-offs.
豆知識＆
トリビア。
Photoshop 1.0 was coded by two brothers working from their parents' basement — Thomas wrote the image engine, John wrote the plug-in API.
The PSD format has a hard limit of 30 000 × 30 000 pixels per layer and 2 GB per file; beyond that you need PSB ("Photoshop Big").
Inside a PSD, layer data can be stored either uncompressed, RLE-compressed, or zip-compressed — editors pick based on content.
Many non-Adobe apps (GIMP, Affinity Photo, Krita) read PSD but rarely preserve 100% of the layer effects — adjustment stacks often break.
The file contains a flattened preview composite so apps that can't parse layers still render something reasonable.
長所と
制限事項。
長所
- Preserves every Photoshop feature: layers, masks, adjustments, smart objects, text, effects, styles.
- Backward-compatible — files from 1990 still open in modern Photoshop.
- Industry-standard handoff format between designers, agencies, and prepress.
- Supports 32-bit HDR, CMYK, Lab, Duotone, and spot colors for professional print work.
- Rich metadata, color profiles, and printing instructions survive round-trips.
制限・弱点
- Proprietary — full fidelity only in Adobe tools; other apps approximate.
- File sizes are enormous (hundreds of MB is common for complex documents).
- Not a web format — browsers cannot display PSD natively.
- Binary structure is complex and version-dependent; parsers often lag the latest Photoshop version.
- Hard 2 GB / 30 000 px limit forces professionals to switch to .psb for large artwork.
一般的なファイルサイズ目安
Simple 2-layer logo
500 KB - 3 MB
Website mockup with 20 layers
20-80 MB
Magazine spread with hi-res photos
150-500 MB
Matte painting / CGI composite
1-4 GB
技術仕様
- MIME type
- image/vnd.adobe.photoshop
- Max dimensions
- 30 000 × 30 000 px (PSD); 300 000 × 300 000 (PSB)
- Max file size
- 2 GB (PSD); 4 EB (PSB)
- Color modes
- Bitmap, Grayscale, Duotone, Indexed, RGB, CMYK, Lab, Multichannel
- Bit depths
- 1, 8, 16, 32 bits per channel
他形式から変換
PSD
主な活用シーン
Graphic design, photo editing, layer-based image composition.
関連フォーマット
よく見られている比較
PSD の人気変換ペア
PSD から変換する際によく選ばれている出力形式です。
PSD に関するよくある質問
よくある 質問
KaijuConverterにPSDファイルをアップロードするだけで、ソフトをインストールせずにPDF、JPG、PNGなどの標準形式へ即座に変換できます。
はい、25MBまで完全無料（24時間パスやProプランでは最大1GB）で変換でき、アップロードされたファイルは60分後にサーバーから自動削除されます。
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1回限りの支払いで24時間、最大1GBのファイルおよび最大50ファイルの一括変換が利用可能です。
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最大1,024 MBの高速クラウド処理、24時間暗号化保持、優先サポート。
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