Why use PSB instead of PSD?

PSB (Photoshop Large Document) is Adobe's extended version of the PSD format, designed for canvases that exceed PSD's 30,000 x 30,000 pixel and 2GB limits. Introduced in Photoshop CS (2003), PSB supports up to 300,000 x 300,000 pixels and a theoretical 4 exabyte file size, making it the working format for billboard-resolution prints, gigapixel panoramic stitches, IMAX matte paintings, digital painters at 60,000 pixels for highly-detailed concept art, satellite imagery composites, and AI-upscaled hero canvases that routinely cross the 2GB threshold.

Converting PSB to HEIC flattens the document and encodes the result as a HEIC image - and here HEIC's efficiency really pays off, since HEVC compression typically lands 40-50% smaller than an equivalent-quality JPEG on gigantic canvases where every percentage point is hundreds of megabytes. HEIC handles huge dimensions by tiling the image into an internal grid (the same mechanism iPhone uses), but many viewers still struggle above roughly 100 megapixels, and HEIC's 10-bit encoding preserves the smooth gradients of matte paintings that 8-bit JPEG would band. For practical sharing, downsize during conversion - 8000 pixels on the long edge is enough for most billboard and large-print review workflows.

Matte painters at ILM, Weta FX, and DNEG; concept artists working on Marvel and Disney productions; medical imaging specialists handling whole-slide pathology scans; cartographers stitching satellite tiles; and large-format printer operators are the typical PSB audiences. Most ship final deliverables as flattened TIFF or a downsized review image because few applications outside Photoshop and Affinity Photo handle PSB natively. For non-massive canvases use PSD-to-HEIC instead. PSB files can take minutes to load even on M2 Ultra workstations with 64GB RAM, so be patient.

Reasons to convert PSB to HEIC usually come down to compatibility, file-size, or specific feature requirements. Common situations:

• An app or platform only accepts HEIC uploads.
• You need a feature unique to HEIC (e.g. transparency, vector scaling, animation, multi-page pages, etc.) that PSB doesn't provide.
• You're optimising file size — modern formats often produce smaller files than the older format you started with.
• You need a single archival format across a project so files behave consistently in the same viewer.

1. Open the PSB → HEIC tool on heic.now.
2. Drag your PSB file onto the drop zone, or click Select files. You can drop a whole folder of files at once.
3. The output is fixed to HEIC. If the format supports extra options (page size, transparency background, quality, EXIF stripping), tweak them in the right-hand panel.
4. Click Convert. The job runs on our server and finishes in a few seconds for typical photos.
5. Download the result. Files stay in storage for 24 hours and are then permanently deleted.

The entire flow is free for the first 10 jobs per day with no signup required. A free account doubles that quota; a premium plan removes the limit entirely.

• Check the canvas size before converting - a 100,000 pixel PSB produces an image few viewers can open regardless of format; downsize during export to 8000-16000 pixels for practical sharing.
• PSB files routinely exceed 4GB and can take 10-30 minutes to load even on fast SSDs; allow conversion time accordingly.
• For Affinity Photo (Mac/Win/iPad) PSB support is read-only - convert to PSD via Photoshop first if you need editable handoff.
• Strip unused layers and merged channels in Photoshop before converting to dramatically speed up flattening on huge canvases.
• Sending review images to a director's iPad? HEIC is ideal - native display, 10-bit gradients intact, and half the download size of JPEG. Sending to a Windows-based print shop? Convert the result via HEIC to JPG first.