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I want to change the Exif data for some .PNG files so that they have the "Date Taken" tag. Is it possible to use that tag on .PNG files?

Is it possible to copy the "Date Modified" date to the "Date Taken" date for then same .PNG file? I'm using ExifTool and I've read in this question that the copying part is possible via exiftool -v "-FileModifyDate>DateTimeOriginal" * but I can't figure out how to use it on the .PNG file.

My questions:

  1. Is it possible to use then "Date Taken" Exif tag on .PNG files?

2.If it is possible, how can I use ExifTool to copy the "Date Modified" tag to the "Date Taken" tag?

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The problem is that the metadata that Windows uses as the "Date Taken" varies by file. For example, for a JPG, Windows will use Exif:DateTimeOriginal if it exists, followed by XMP:DateTimeOriginal, followed by CreateDate, followed by FileCreateDate (the system file create date). (Off topic, if anyone has a link that lists details of all the types of files and metadata that Windows uses under the "Choose Details" list, I'd appreciate it).

Now, ExifTool will happily create an Exif block in a png for you, though I'm guessing it may not be standard. XMP blocks as well. But my quick testing shows that Windows will not read either of those items for the Date Taken.

It looks like the tag you want to use is PNG:CreationTime. That shows up in Windows as the Date Taken for me (Win 8.1). So your command would be:
ExifTool "-PNG:CreationTime<FileModifyDate" FILE/DIR

  • Thank you for the help, "ExifTool -v "-PNG:CreationTime<FileModifyDate" -overwrite_original *" solved the problem. – Dempa Jun 14 '15 at 10:52
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No. PNG does not support EXIF. In fact, lack of a standardized metadata block is one of its big disadvantages for photography. If you need a lossless format which preserves (very-similar-to-EXIF, since it's the basis for EXIF) metadata, try TIFF. The downside, though, is that TIFF rendering support is not as widespread as that for PNG (for web applications and other consumer-level display kind of things — for all but the most basic image editing applications, TIFF is everywhere).

  • Does TIFF have support for "Date Taken" tag? How can I easily convert all of these .PNG files to .TIFF and preserve the "Date Created" or move it to "Date Taken"? – Dempa Jun 12 '15 at 19:39
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    @Dempa In Linux, or similar: 1. convert sample.png -compression lzw sample.tif 2. touch --reference=sample.png sample.tif 3. exiftool '-FileModifyDate>DateTimeOriginal' sample.tif – mattdm Jun 13 '15 at 1:15
  • I would qualify that statement about "TIFF rendering support is not as widespread as that for PNG" a little bit... this is very much true if we're talking about web formats, but TIFF has a very long history of support in imaging applications. – junkyardsparkle Jun 13 '15 at 3:26
  • @junkyardsparkle Yeah, good clarification. I've expanded a bit. – mattdm Jun 13 '15 at 3:35

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