What's inside a PSD file
A PSD is a working file, not a finished picture. It can hold:
- Layers: photos, painted pixels and graphics stacked on top of each other and organized in groups. Our guide to using layers shows them in practice.
- Text layers that stay editable, as long as the font is available.
- Masks: pixel and vector masks that hide parts of a layer, and clipping masks that confine one layer to the shape of another. Here's what a layer mask does.
- Adjustment layers such as Curves or Levels, which change the colors below them without altering the pixels.
- Layer styles such as Drop Shadow or Stroke, and smart objects, which keep an embedded or linked image editable.
- Artboards, for several designs in one file, and color depths of 8, 16 or 32 bits per channel.
Adobe describes PSD files as able to "store multiple layers of content, images, and objects, often in high resolution". That's why a PSD is usually much bigger than a PNG or JPG of the same image.
What PSD files are used for
Adobe names two main uses: digital design, where people work with many layers and graphic elements, and photo editing, such as retouching and compositing. You'll also come across PSD files as templates and mockups, as website or app designs from a designer, and as print artwork before it's exported.
PSD, PSB, PNG and JPG compared
| Format | Keeps layers | Transparency | Typical size | Use it for |
|---|---|---|---|---|
| PSD | Yes | Yes | Large | Working files you'll edit again |
| PSB | Yes | Yes | Very large | Documents beyond PSD's limits |
| PNG | No | Yes | Medium to large | Graphics, logos and screenshots |
| JPG | No | No | Small | Photos to share or publish |
According to Adobe, a PSD can be up to 30,000 pixels high and wide and up to 2 GB in size. PSB, short for "Photoshop Big", is the larger form for documents beyond that.
How to open a PSD file
- In your browser: open it online with PhotopixPro. It shows the layers and lets you edit and export them, with nothing to install or upload.
- On a Mac: Adobe says the Preview app opens and views PSD files, without editing.
- Desktop programs: GIMP and Krita, both free, can read PSD files.
- On a phone: Adobe says its Photoshop Express app opens PSD files on iPhone and Android.
The full step-by-step, device by device, is in our guide on how to open a PSD file without Photoshop.
Converting a PSD
When someone only needs the picture, send them a PNG or JPG instead of the PSD:
- PSD to PNG keeps transparency and every pixel, which suits graphics.
- PSD to JPG gives a much smaller file, which suits photos.
PhotopixPro doesn't export PDF. For future edits, keep the PSD: once the layers are merged into a PNG or JPG, you can't separate them again.
Why a PSD can look different outside Photoshop
GIMP's developers note that the public PSD specification isn't always complete, and Krita's documentation says no program outside Photoshop can support PSD 100%. The usual differences are fonts that aren't installed, some layer effects, and the lookup tables used by Color Lookup adjustments. PhotopixPro warns you when a font or a lookup table is missing.