Adobe Photoshop Document
PSD is Adobe Photoshop's native project format, storing the full layer stack — blend modes, masks, adjustment layers, smart objects, and text — in a 5-section binary structure. The merged composite image at the end allows quick preview without parsing the layer tree.
Photoshop files contain proprietary layer data, blend modes, and smart objects requiring Adobe's rendering engine.
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How do I open a PSD file without Photoshop?
Use Photopea (photopea.com) — a free browser-based editor that parses PSD layer structure, blend modes, and text layers with near-complete fidelity. GIMP and Affinity Photo also import PSD files, though some Photoshop-specific effects may be lost.
What is the difference between PSD and PSB?
PSD supports images up to 30,000 x 30,000 pixels with a 2 GB file size limit. PSB (Large Document Format) extends these limits to 300,000 x 300,000 pixels and effectively unlimited file size. The binary structure is identical — PSB uses 8-byte offsets where PSD uses 4-byte.
Can I extract individual layers from a PSD without Photoshop?
Yes. ImageMagick exports layers by index: magick convert 'input.psd[1]' layer1.png extracts the first layer. Photopea provides full layer panel access in the browser. GIMP also imports the PSD layer stack.
Does converting PSD to PNG lose layer information?
Yes. PNG is a flat raster format with no layer concept. Converting PSD to PNG renders the merged composite — all layers, effects, and masks are baked into a single image. Keep the original PSD for future editing.
ما يميز .PSD
What is a PSD file?
PSD (Photoshop Document) is the native file format of Adobe Photoshop, the industry-standard image editing software. PSD files preserve all editing information including layers, masks, adjustment layers, text, shapes, and blending modes, allowing non-destructive editing. The maximum file size is 2 GB (PSB for larger files).
اكتشف التفاصيل التقنية
How to open PSD files
- Adobe Photoshop (Windows, macOS) — Full editing support
- GIMP (Windows, macOS, Linux) — Free, partial layer support
- Photopea (Web) — Free online editor, excellent PSD support
- Affinity Photo (Windows, macOS) — Full PSD support
Technical specifications
| Property | Value |
|---|---|
| Max Dimensions | 30,000 x 30,000 px (PSD), 300,000 x 300,000 px (PSB) |
| Color Modes | RGB, CMYK, Grayscale, Lab, Bitmap |
| Bit Depth | 8, 16, 32 bit per channel |
| Layers | Unlimited |
| Max File Size | 2 GB (PSD), 4 EB (PSB) |
Common use cases
- Graphic design: Logo, banner, and poster creation.
- Photo editing: Professional retouching and compositing.
- Web design: UI mockups and asset creation.
- Print production: High-resolution print-ready files.
المرجع التقني
- نوع MIME
image/vnd.adobe.photoshop- Magic Bytes
38 42 50 538BPS signature.- المطوّر
- Adobe Systems
- سنة التقديم
- 1990
- معيار مفتوح
- لا
8BPS signature.
البنية الثنائية
PSD files are organized into five sequential sections. Section 1: File Header (26 bytes) — signature '8BPS', version (1 for PSD, 2 for PSB), 6 reserved bytes, channel count, height, width, depth, and color mode. Section 2: Color Mode Data — palette data for indexed/duotone modes (length-prefixed, empty for RGB/CMYK). Section 3: Image Resources — variable-length blocks prefixed with '8BIM' signature containing resolution info, slices, ICC profile, alpha channel names, and other metadata. Section 4: Layer and Mask Information — the core of the format, containing layer count, per-layer records (blend mode, opacity, clipping, flags, channel data, mask data, layer name), and global layer mask info. Section 5: Image Data — the merged composite (flattened) image, preceded by a 2-byte compression method flag (0=raw, 1=RLE). Readers that only need a preview can skip sections 2-4 and render section 5 directly.
| Offset | Length | Field | Example | Description |
|---|---|---|---|---|
0x00 | 4 bytes | Signature | 38 42 50 53 | ASCII '8BPS'. Identifies the file as a Photoshop document. |
0x04 | 2 bytes | Version | 00 01 | 1 = PSD (max 30000x30000, 2 GB limit). 2 = PSB (max 300000x300000, 4 EB limit). |
0x06 | 6 bytes | Reserved | 00 00 00 00 00 00 | Must be zero. Non-zero values indicate corruption or a non-standard writer. |
0x0C | 2 bytes | Channels | 00 04 | Number of channels including alpha. Range: 1-56. |
0x0E | 4 bytes | Height | 00 00 04 00 | Image height in pixels (big-endian). PSD max: 30000. PSB max: 300000. |
0x12 | 4 bytes | Width | 00 00 05 00 | Image width in pixels (big-endian). PSD max: 30000. PSB max: 300000. |
0x16 | 2 bytes | Depth | 00 08 | Bits per channel: 1, 8, 16, or 32. |
0x18 | 2 bytes | Color mode | 00 03 | 0=Bitmap, 1=Grayscale, 2=Indexed, 3=RGB, 4=CMYK, 7=Multichannel, 8=Duotone, 9=Lab. |
نقاط الضعف
- Malformed Image Resources (section 3) with crafted 8BIM blocks can trigger buffer overflows in parsers
- Layer records with extreme channel counts (up to 56) and large dimensions can cause memory exhaustion
- Embedded ICC profiles with malformed tag tables exploit color management libraries (e.g., CVE-2009-0793 in lcms)
- Smart Object payloads can embed arbitrary file types — a PSD can contain an embedded PDF, EPS, or another PSD
الحماية: FileDex does not parse PSD layer structure in the browser. PSD is a reference-only page. Users requiring conversion should use Photopea (browser-based) or local tools like ImageMagick.