How do I write info on PNG files so it can be read by Photoshop ?

[mitchboo]

I am able to write info on JPG files that can be read by Photoshop, but PNG still evades me. I searched StackOverflow, and read many pages that talk about the XMP option as well as how XMP can be written before, but none of the command lines I try work.

I went through the FAQ, as well as the EXIFTool site. PNG is mentioned, but there is no actual command line example.

What would be the typical command line to add a comment to a PNG file that Photoshop can read ? Is it even possible ?

Thanks in advance for any pointer.

[StarGeek]

What version of Photoshop?

From what I've heard, Adobe has expanded what their programs can read in more recent versions (Creative Cloud versions), but earlier versions have very little support for metadata in PNG files.  I only have LR 4.4 and it does almost nothing with metadata and PNGs.

[mitchboo]

I tried with Photoshop Element 15.

It works perfectly for jpeg and Tiff.

[StarGeek]

Try setting the metadata you're interested in on a PNG in Elements.  Then use exiftool -g1 -a -s FILENAME to see where that data was saved.

[mitchboo]

Try setting the metadata you're interested in on a PNG in Elements.  Then use exiftool -g1 -a -s FILENAME to see where that data was saved.

Thank you StarGeek. But precisely, what is the command line I can use to set the metadata in a png ?

Thank you.

MitchBoo

[Phil Harvey]

StarGeek suggested writing the metadata with Photoshop Elements, then reading back with exiftool to see where it was written.  Once you have done that, post the results here and we can help with the exiftool command line to write the same information.

If Elements can't write what you want to a PNG file, it is likely that it won't read it back either.  Adobe has been very poor at supporting metadata in PNG images.

- Phil