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I want to tag some images. I'm wondering which is the right place in the EXIF to store specific information about the scene. For example: Cat, Nature, etc.

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There are a number of metadata standards used in photography. EXIF is one of them, but there are others in common use as well. Today's image files often include multiple metadata sections in different formats.

EXIF is most concerned with metadata from the camera about the shooting situation: exposure parameters, image data structure, and etc. It has a few fields that are descriptive, but these have some serious limitations (for example, this is supposed to be pure ASCII — Unicode is not allowed, so no characters outside the basic English alphabet). It's not really very rich for description and categorization.

Instead, I encourage you to use XMP for this. XMP is a modern, flexible standard understood by a wide variety of modern software.

In XMP, the tag "Subject" is meant to be a list of keywords, just like you've provided. This is very commonly used in the real world — for example, if you upload images with XMP Subject tags to photo-hosting service Smugmug¹, those tags will automatically get turned to Keywords. ("Title" and "Caption" are also widely understood.)


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    Just to clarify a possible misunderstanding of terms by the OP, EXIF data is only one type of image metadata. There is also IPTC (IIM) and XMP (which includes the newer IPTC Core), as well as other obscure types (such as Ducky). To put it simply, all EXIF data is metadata, but not all image metadata is EXIF. – StarGeek Mar 11 at 17:05
  • @StarGeek I think EXIF is stored within the image by the camera.I don't want to use any extra software or put any additional file. – techno Mar 12 at 4:27
  • @techno XMP is also stored in the image. There is no camera I am aware of which will put category metadata (in any format) directly into the image directly from the camera itself. – mattdm Mar 12 at 4:40
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    @techno What you see when you hit the Details tab is what data Windows pulls from any EXIF, IPTC IIM, and XMP chunks embedded in the file. If you fill in the data there and let Windows write it out, it will write it out to a variety of fields. I've documented some of this behavior over in the Exiftool Forum. And as madddm said, the other types of metadata are embedded in the file, though XMP metadata can also be placed in a sidecar file. – StarGeek Mar 12 at 5:34
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    See my last comment where I give a basic command. MWG:Keywords will also populate IPTC:Keywords. The reason I suggested the MWG tag is because it will populate multiple tags at once, meaning you are less likely to need to worry about what type of tags your software will read in the long run. Also make sure and read the FAQ 17 I linked, so you understand how to add keywords without overwriting any existing keywords. – StarGeek Mar 13 at 21:07
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The question is a bit too broad but for me the place to store this king of information is tag:

0x010e  ImageDescription

Of course you can select own tag like

0xc44f  Annotations

More tags, appropriate for such info can be:

0x927C MakerNote
0x9286 UserComment

You can check also in Exif specification here

  • I have upvoted your answer.But chose the other one since it adds details about the possible issues with EXIF and also because of the useful comments under it. – techno Mar 14 at 6:17
  • @techno, I add few more. If you do not like EXIF solution please consider using XMP, IPTC and so on – Romeo Ninov Mar 14 at 6:50
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    okay..thanks :) – techno Mar 14 at 6:51
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Alternatively, you could leverage something called IPTC. It's like EXIF, but it's used a little bit differently.

Designed for working professionals, IPTC is primarily used to tag a type of photo and to embed copyright information into it. IPTC allows you to change all sorts of information, including

  • Overwriting or attaching a caption or description
  • Adding a headline
  • Attaching copyright and contact information
  • Licensing information,
  • Manual location entry (location, sublocation, city, state, country, ISO country code, continent)
  • Models or artwork information
  • and more!

IPTC, EXIF, and other metadata forms can be stored in something called sidecar files, which take the form of XMP files, or eXtensible Metadata Platform. When you change the metadata, even through editing in Photoshop (yes, the metadata changes behind the scenes), you may have noticed that the software creates a second file that can be opened in Notepad or the macOS equivalent. That's the sidecar file, and it's carrying all of the juicy metadata information as a "backup" of sorts, helping the main image file. Most of the time, you may not even see this sidecar file, but it's there.

You can use programs like Photoshop or Photoshop Lightroom to edit this metadata, though some softwares handle metadata editing and saving better than others. My weapon of choice is Photo Mechanic, as it handles sidecar files very well.

If you got curious about what XMP metadata looks like for photos: <x:xmpmeta xmlns:x="adobe:ns:meta/" x:xmptk="Adobe XMP Core 5.6-c140 79.160451, 2017/05/06-01:08:21 "> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"> <rdf:Description rdf:about="" xmlns:tiff="http://ns.adobe.com/tiff/1.0/" xmlns:exif="http://ns.adobe.com/exif/1.0/" and on and on and on. It's several hundred lines of information!

Edit: Tl;dr: Information about what the photo contains should be packaged in the IPTC Description/Caption field. EXIF is a type of metadata, but its purpose is NOT to describe the contents of the photo, but rather the camera and its settings.

  • Are you sure EXIF need a separate file? – techno Mar 12 at 4:28
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    EXIF, IPTC, and most other metadata CAN be stored internally, neatly packaged within the image file, but that doesn't mean that it SHOULD be. Don't worry about tacking on an XMP file next to an image file. If it needs to be done, then the program in charge will say so by just doing it. Try opening a RAW file in Photoshop. In the image's folder, an XMP file will magically appear! – Sejin Kim Mar 12 at 4:38
  • okay..thanks..... – techno Mar 13 at 5:57
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In passing on adding keywords:

If you have the keyword cat you will get your pussycat, but also caterpillar (insect); caterpillar (earth moving equipment); caterpillar (brand) catastrophe, every girl named Catherine...

There are two approaches to this. Not mutually exclusive.

  1. You use a hierarchical keyword list. Birds > Falcon is different from Cars > Ford > Falcon is different from Ships > British war ships > Falcon > ...

  2. You facet you keywords by using prefixes. E.g

    P: what follows is a person
    L: what follows is a place name
    WE: what follows is weather
    SK: what follows is a sky attribute.
    LAND: what follows is a landscape attribute
    T: what follows is a time of day lighting attribute.

That last one: Time of day is standard Exif data for any digital image. But pics during the golden hour or blue hour or civil twilight have a certain quality to them.

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