I'm working with some big .psd scan files that have just 1-2 adjustment layers.

These files are going to be further edited and managed in Lightroom. To both keep the adjustments and but have Lightroom able to edit the files, I have checked Maximize Compatibility, however, I like to keep the adjustment layers.

Photoshop Maximize Compatibility Dialog

This mode basically include a flattened version inside the original .psd file with the layers, allowing greater compatibility with other software that does not support layers.

If I save the file this way, the file is editable by Lightroom. But it takes a huge amount of space (basically doubled because of the embedded flattened version).

If I save the file without compatibility the file is the size I want, but Lightroom can't open it because it doesn't understand photoshop layers.

Isn't this weird? Lightroom is Adobe software, but can't understand Photoshop layers. To have the file edited, it must be flattened. Maybe with a .tiff file that seems to be more standardized I could have more luck?

The goal here is avoid to waste the space 2 times having to keep the embedded image aside the separated layers.


2 Answers 2


If you want minimal file size while still maintaining compatibility with Lightroom you should use TIFF (ZIP compressed for 16bpc, LZW compressed for 8bpc, as recommended here). I just did a test with a photo I had laying around (7360×4912 pixel, 16bpc):

Background layer only      TIFF ZIP          183.5 MB
Background layer only      PSD               217.0 MB

BG + 2 adjustment layers   TIFF ZIP          345.6 MB
BG + 2 adjustment layers   PSD no comp.      165.5 MB
BG + 2 adjustment layers   PSD max. comp.    379.0 MB

As you can see the TIFF file is somewhat smaller than the PSD file with "Maximize Compatibility" on. There are also arguments against using PSD in general and for using TIFF instead, so that might be your best option.

Another route that will definitely save the most space would be to make the relevant adjustments in Lightroom instead of in Photoshop, but I suspect that's not an option in your case.

PS: Nope, I do not know why the PSD file with just the Background layer ended up bigger than the one without "Maximize Compatibility" plus the two adjustment layers. Yes, I disabled "Maximize Compatibility" in the options, but it doesn't seem to make a difference with flattened files (and it shouldn't, logically).

  • \$\begingroup\$ Sadly it seems that the only gain in using the .tiff file in this case is the ZIP compression applied 345 vs 379. I bet that TIFF ZIP file also retain a full flatterned copy of the original file otherwise the 345 MB vs 183 does not make any sense. A 9% compression gain is not enough to save space effectively :\ \$\endgroup\$ Commented Oct 9, 2016 at 15:55
  • \$\begingroup\$ That definitely seems to be the case, yes. Adding a uniform white layer on top decreases the TIFF file size (BG + 2 adjustment layers) to 162.8 MB, very close to the PSD without Maximize Compatibility. \$\endgroup\$
    – Graumagier
    Commented Oct 9, 2016 at 16:10

Isn't this weird? Lightroom is Adobe software, but can't understand Photoshop layers.

PS and LR are simply different tools. PS has more features which get saved in the file. LR has no way to interpret this information in the file, because it doesn't have the same tools.

To combine PS and LR in one workflow, start in LR, then choose edit photo in PS from within LR. This takes the image on a roundtrip to PS and back. This keeps the file handling behind the scenes. If file size is kept minimal in the process is something I don't know and you would have to try.

  • \$\begingroup\$ In this case you would have to use either TIFF as an interchange format, or PSD with "Maximize Compatibility" enabled. Lightroom cannot import PSDs without "Maximize Compatibility" enabled, nor can it create one in the workflow you describe (more specifically, Photoshop creates the PSD file after reading whatever image file you send to it from within Lightroom). \$\endgroup\$
    – Graumagier
    Commented Oct 9, 2016 at 15:16

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