PSD file ImageData compression tag

[fpria]

I'm having trouble reading whether the PSD file is compressed or not.
In Photoshop settings you can change whether the file should be compressed or not.


Regardless of how I save the file, ExifTool always returns the "Compression" tag value as RLE.

My steps to reproduce:

• Create a PSD file with several layers and save it with compression turned on.
• Disable compression and save the file again. The file size has increased so it is definitely not compressed, but the ExifTool still returns: Compression: RLE

Phil, can you confirm if it's a bug in ExifTool or not?

[StarGeek]

Try using the command in FAQ #3 to make sure you are looking at all the tags, including duplicated named tags, as well as the locations those tags are in.  Also, the actual tag you really want may be a different tag.

[fpria]

Try using the command in FAQ #3 to make sure you are looking at all the tags, including duplicated named tags, as well as the locations those tags are in.  Also, the actual tag you really want may be a different tag.

I confirm, I am checking the correct tag.

[Phil Harvey]

Can you post 2 identical (small) files, one compressed and one not?

- Phil

[fpria]

Two files here, one compressed, one not.

[Phil Harvey]

You're right.  The compression values are the same.  I can't say why, but ExifTool is extracting them properly.

- Phil

Code Select Expand

> exiftool uncompressed.psd compressed.psd -compression -a -G1
======== /Users/phil/Desktop/uncompressed.psd
[IFD0]          Compression                     : Uncompressed
[IFD1]          Compression                     : JPEG (old-style)
[Photoshop]     Compression                     : RLE
======== /Users/phil/Desktop/compressed.psd
[IFD0]          Compression                     : Uncompressed
[IFD1]          Compression                     : JPEG (old-style)
[Photoshop]     Compression                     : RLE
    2 image files read

[blue-j]

Seems like a bug in Photoshop.  The value should be "0" or "RAW" for the uncompressed PSD.  The compressed document looks correct (PSD compression is RLE).  I hope you might find the time to report it!

https://www.adobe.com/products/wishform.html

- J

[fpria]

Yes, it's probably a Photoshop bug. Nevertheless, the files open, so Photoshop probably doesn't use the value of the "Compression" field at all.
Do you know a method on how to recognize if data is RLE compressed or not without fixing this bug in PS?

[fpria]

Update:
I found that ImageMagick correctly recognizes my files. The compressed ones shows the ZIP value in Compresssion field.
According to Adobe standards, PSD files support this compression type.