Earlier today, I was asked to settle a dispute between two of my co-workers. They were talking about a recent conversation had with a customer and one said that they were scaling an image with Genuine Fractals that was 20 feet by 30 feet at 300 ppi. One of my co-workers didn’t think that Photoshop would let you save a file that big. So I was asked who was right? There was a lunch on the line here afterall.
The answer is that if you’re using Photoshop CS2, you can indeed create a file that is 20 feet by 30 feet at 300 ppi – In fact you could go bigger if you wanted as long as you turn on the preference to enable large document support (.PSB files) in Photoshop’s preferences. Doing so, you can go up to 300,000 pixels by 300,000 pixels. At 300 ppi, that’s 1,000 inches or 83 and some odd feet. That’s pretty big indeed.
In earlier versions of Photoshop, you were limited to 30,000 pixels in height and width and at 300 ppi, that’s only 100 inches (8.3 feet) so, in a sense, both of my esteemed colleagues were correct depending on the version of Photoshop they were referring to.
So who should get the lunch? If you ask me…well, me. 
If you want to turn on PSB support, just go to your Photoshop Preferences and check the box to enable the large document format (see screenshot below).
