I'm building a large landscape montage using about 50 RAW images at 16Mb per image. I've successfully managed processing montages before that were 1.5 Gb but over the course of the few hours it took my rig to process them, they pretty nearly melted my core.

Besides the normal stuff that allows PS to run (setting cache and scratch disk size), is there something else I should be doing to run huge files efficiently? Like...

Should I skip working with uncompressed TIFFs and save straight to JPEGs? When building intermediate sections, should I flatten my image to reduce file size? I really like the flexibility of post processing an uncompressed image when doing final editing, but I don't want to wait for several hours only to discover that PhotoShop has locked up my machine.

  • \$\begingroup\$ Every time you add a layer or a mask, that's more memory that hungry PS chows down on. \$\endgroup\$
    – Octopus
    Jan 24, 2017 at 8:59
  • \$\begingroup\$ the title and body of the post ask very different questions. You might want to commit to only one of them. \$\endgroup\$
    – ths
    Jan 24, 2017 at 10:18

1 Answer 1


Here you can see the maximum size of different file formats in Photoshop

PSD files: 2 GB

TIFF files: 4 GB

PSB files: 4 exabytes (4096 petabytes or 4 million terabytes)

PDF files: 10 GB (pages are limited to a maximum size of 200 inches)

Also per same document the maximum dimensions (in pixels) are:

Photoshop supports a maximum file size of 300,000 x 300,000 pixels, except for PDF files, which are limited to 30,000 x 30,000 pixels and 200 x 200 inches

  • 1
    \$\begingroup\$ That same part of that same link also says, "300,000 x 300,000 pixels". I believe that's more along the lines of what the OP is asking. What can PS handle, not what the file formats are capable of. That's a total of 90Gb. Of course it will depend on how much RAM is installed in their machine. \$\endgroup\$
    – Octopus
    Jan 24, 2017 at 8:54
  • \$\begingroup\$ Thank you, @Octopus, will add the pixel limits in answer \$\endgroup\$ Jan 24, 2017 at 8:56
  • 1
    \$\begingroup\$ Thanks for that link, Romeo..... I'm going to call yours the answer, even if it's for the CC version. \$\endgroup\$ Jan 25, 2017 at 16:35

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