Very valid comment, and thanks for detailing some of the differences between how Mac, Windows, Lightroom and Bridge treat metadata. It is disappointing to see these variations, especially given that the EXIF and IPTC standards are so well documented and very clear.

Some IPTC definitions below:

Title (Max 64 characters): A short human readable reference for the image. It has been used by photographers for filename, though IPTC now provides specific fields for image IDs like Digital Image GUID or Registry Entry. The Title field should not be confused with the Headline field (See below).

Headline (Max 256 characters): A brief synopsis or summary of the contents of the photograph. Like a news story, the Headline should grab attention, and telegraph the content of the image to the audience. Must be succinct . Leave the supporting narrative for the Description field.

Description/Caption (Max 2,000 characters): The Description field, often referred to as a caption, is used to describe the who, what, where,when and why of what is happening in the photograph. It can include people’s names, their role in the action, and the location. (Location should also be put in the appropriate IPTC Location fields (which also provide for sub-location, state, country, country code etc.)

The XMP standards developed by Adobe, which are an extension of the IPTC standards, have no limits for the number of characters in the above fields.

Our original article mentions two programs: Adobe Lightroom, which follows XMP standards, and SnipTag, which follows IPTC standards.

Most photo programs index everything you put into metadata. So it should be possible to search for a photo in any program on any OS, as long as the search word exists somewhere in the metadata. But not being able to use the descriptions you have painstakingly added with one program in another program, or in one operating system on another, is frustrating.

Lastly, news for Windows users: There is no field named Comments in IPTC standards. Whatever you enter into this field using Windows Explorer will not be searchable by any other third party programs.