The Large Document Format (PSB) supports documents up to 300,000 pixels in any dimension. All Photoshop features, such as layers, effects, and filters, are supported. You can save high dynamic range, 32‑bits-per-channel images as PSB files. Currently, if you save a document in PSB format, it can be opened only in Photoshop CS or later. Other applications and earlier versions of Photoshop cannot open documents saved in PSB format.