What is PSD (Photoshop Document)?
Complete guide to the PSD file format
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What is PSD (Photoshop Document)?
PSD is Adobe Photoshop's native file format. It stores all the layer information, effects, masks, and editing history of a Photoshop project in a single file.
PSD files preserve every aspect of a Photoshop composition including multiple layers, adjustment layers, text layers, smart objects, blending modes, and layer masks.
How PSD Stores a Composition
The PSD file is organized into a fixed header, color mode data, image resources, a layer and mask section, and a flattened composite image preview used by applications that cannot interpret layers.[2] Pixel data is stored either raw or compressed with PackBits run-length encoding, and the format records each layer's blending mode, opacity, masks, and effects so an edit can be resumed exactly where it left off.[2]
History and Size Limits
PSD originated with the first release of Adobe Photoshop in 1990 and has remained the application's native format ever since.[4] The classic PSD format is limited to 30,000 pixels per dimension and a 2 GB file size; to overcome this, Adobe introduced the PSB ("large document") variant that supports up to 300,000 pixels and far larger files.[1]
PSD vs Flattened Formats
Unlike JPEG or PNG, which store only the final rendered pixels, PSD preserves the full editable project, including adjustment layers, text layers, smart objects, and layer masks.[3] This makes PSD ideal as a working master file, but its size and partial support outside Adobe software mean it is typically exported to a standard format for sharing or web use.[1]
Technical Details
PSD vs Other Image Formats
| Feature | PSD | TIFF | PNG |
|---|---|---|---|
| Type | Raster (layered)[3] | Raster | Raster |
| Layers | Yes[3] | Limited | No |
| Compression | Lossless (RLE/none)[2] | Lossless or none | Lossless |
| Transparency | Yes[3] | Yes | Yes |
| Owner | Adobe[1] | Aldus/Adobe | W3C |
| Best for | Layered editing | Archival imaging | Web graphics |
PSD preserves layers and editing data for Photoshop work, while TIFF and PNG are better suited to flattened distribution and broad compatibility.
Pros and Cons
Advantages
All layers, masks, and effects are fully preserved for future editing.
PSD is the industry standard for graphic design and photo editing workflows.
Supports smart objects, adjustment layers, effects, and all Photoshop features.
PSD supports CMYK color mode required for professional print production.
Disadvantages
Complex PSD files can be hundreds of megabytes or even gigabytes.
PSD is primarily an Adobe format - other apps have limited or incomplete support.
PSD cannot be used directly on websites - must be exported to JPEG, PNG, or WebP.
Large PSD files take significant time to open and process.
When to Use PSD (Photoshop Document)
Here are the most common situations where PSD (Photoshop Document) is the right choice:
Graphic Design
PSD is the primary format for all Adobe Photoshop graphic design work.
Photo Retouching
Professional photo retouching uses PSD to preserve all editing layers.
Web Design Mockups
Web designers create mockups in PSD before exporting assets for development.
Print Design
CMYK PSD files are the standard deliverable for professional print design.
Convert PSD (Photoshop Document) Files
Need to convert your PSD files? Use our free online converter.
Try Image Converter FreeFrequently Asked Questions about PSD (Photoshop Document)
Can I open PSD without Photoshop?
Yes, Affinity Photo, GIMP, and Preview (Mac) can open PSD files, though with some limitations.
How do I convert PSD to PDF?
Use Photoshop (File > Export) or our free online converter to convert PSD to PDF.
Can I open PSD in Illustrator?
Illustrator can open PSD files but may not preserve all Photoshop-specific features.
What is the difference between PSD and PSB?
PSB (Large Document Format) supports files larger than 2GB. PSD has a 2GB file size limit.
How do I flatten a PSD?
In Photoshop, go to Image > Flatten Image. This merges all layers but reduces file size significantly.