Editor › Learn › The PSD Format Explained: What Is Inside a Photoshop File
What is a PSD file and what does it actually contain?
PSD is Adobe Photoshop's native format: a container that stores the full editing structure of a document — raster layers with masks, adjustment layers with their parameters, text layers with live type, layer effects, blend modes, paths and channels — plus a flattened composite so any reader can at least show the image. It is the de-facto exchange format for layered work, which makes its compatibility rules worth understanding precisely.
A container of editing intent
A JPEG stores the finished picture; a PSD stores how the picture is MADE. Each layer keeps its own pixels, position, opacity, blend mode and masks; adjustment layers store parameters (a curve, a hue shift) that are re-applied live; text layers store the string and its styling; effects store their recipes. This is why a PSD can be reopened and every decision revisited — and why its file size dwarfs the flattened image.
Crucially, the format also embeds a flattened composite. Software that understands nothing about layers — file browsers, placement into layouts — reads that composite. This dual nature is what made PSD a workable exchange format far beyond Photoshop itself.
What third-party editors can and cannot preserve
Any editor other than Photoshop implements PSD from the published specification plus observed behaviour, so fidelity is a spectrum. Structure — layers, groups, masks, opacity, common blend modes — round-trips well across serious implementations. The historical breaking points are live effects (drop shadows, glows and styles may rasterise or drop), text (fonts and advanced type features may not survive as live type), smart objects, and exotic adjustment types.
PhotoAIA opens and exports layered PSD with raster layers, groups, masks, common blend modes, text and the adjustment types it implements; its known-limitations page states exactly which constructs rasterise or drop on import, because a designer deserves to know BEFORE the file matters. Whatever editor you use, the honest test is a round trip of one representative file from your own workflow.
PSD, PSB and when TIFF quietly wins
- PSD has hard limits: 30,000×30,000 px and 2 GB. Beyond them Photoshop switches to PSB (Large Document Format), which fewer third-party tools read.
- Layered TIFF can carry Photoshop layers too — many studios archive in TIFF for its openness and streaming-friendly structure.
- For final DELIVERY to print, neither: flattened TIFF or a print PDF is what output devices consume. PSD is a working and exchange format.
Practical hygiene for exchanged PSDs
- Embed the colour profile — a layered file with stripped meaning is wrong in every editor equally.
- Name layers and groups; the next person's time is part of the deliverable.
- If the receiver only needs the image, send a flattened format and keep the PSD as YOUR master.
- Before a critical hand-off between different editors, round-trip one test file and check text, effects and adjustment layers explicitly.
Questions
- Can I open a PSD without Photoshop?
- Yes — several editors including PhotoAIA open layered PSD in the browser. Fidelity varies by construct; check the editor's stated limitations against what your files use.
- Why is my PSD so much larger than the exported image?
- It carries every layer's full pixels plus masks, channels and the composite. Size tracks the sum of the structure, not the final picture.
- Does saving a PSD from another editor destroy Photoshop compatibility?
- A correct implementation writes files Photoshop reopens fine; constructs the other editor had to rasterise stay rasterised. The round-trip test on your own material is the definitive answer.