This dialog allows you to configure which metadata IMatch imports into the database. This enables you to increase the performance and to reduce the size of the database file on disk. You can also configure IMatch to import specific metadata tags you are interested in.
If you are migrating an older IMatch database to IMatch 2017.2.10 or newer (you open an older IMatch database for the first time), perform these steps:
Metadata is an important part of IMatch. When adding or updating files, IMatch imports metadata from the files into the IMatch database. This not only allows quick access to the data (even if the original file is off-line), but also makes features like collections, data-driven categories or searching possible.
At the last counting, IMatch supported over 18,000 of individual metadata tags via ExifTool. Some of this metadata is very important, e.g. XMP metadata or the EXIF data camera stores in image files. Or IPTC metadata when you work in a professional environment or deliver files to web sites and agencies.
But the most part of the metadata contained in image files is not of interest for humans. Modern digital cameras store literally hundreds of metadata tags in each file, from less informative camera settings to large chunks of binary data of all sorts. RAW Processors software often add large amounts of data inside custom namespaces in XMP metadata. A modern RAW image may contain between 200 and 800 (eight hundred!) metadata tags - especially when you have processed the file with a RAW Converter that stores settings inside XMP (e.g. many Adobe products). If you work with Adobe Photoshop™ and you let it store a complete history inside the image file, thousands of additional metadata tags may be stored inside PSD or XMP files.
You will never look nor use most of this metadata.
IMatch splits the supported metadata tags into two groups: Mandatory and Optional. Mandatory metadata is always imported, optional metadata can be imported on a per-group and per tag basis. IMatch users can control which optional tags are imported.
Examples for mandatory metadata are XMP, IPTC, EXIF, certain tags contained in the Lightroom namespace (e.g. hierarchical keywords) or the Camera Raw namespace (crop information). This information must be imported into the database in order for IMatch to work properly.
Optional metadata are the custom tags written by camera vendors like Nikon, Canon or Panasonic. This data often consists of hundreds of tags per file, and only some of these tags may be useful or informative.
For example, if your camera records a specific setting in a proprietary metadata tag, and you want to include this data in the database to use it for sorting, searching or data-driven categories. In this case you are be able to tell IMatch to include this tag, but leave the other proprietary tags out of the database.
Which and how much metadata IMatch imports from files does not affect features like writing metadata, copying data between files, propagation etc. When writing or updating metadata, IMatch/ExifTool always work with the data actually stored in the file.
A typical RAW file that has been developed/edited by a modern RAW processor may contain up to 600 metadata tags. Only 100 - 150 of these tags fall into the mandatory category. The other 450 to 500 tags are superfluous, proprietary, undocumented or plain useless.
By importing only mandatory metadata and leaving out vendor-specific tags and maker notes, IMatch can often reduce the amount of data to cache in the database by 40% to 60%.
Consider a database with 100,000 image files. Most of the files are RAW and many of these files have been touched by a RAW processor. If IMatch would store 500 metadata tags for each file, the total number of metadata tags in the database would be 50 million. A lot of data to sort, search and move around. By concentrating on mandatory tags only, IMatch can bring that number down to maybe 10 to 12 million records. And that's a lot less data to deal with! Many operations will become 5 times faster when only 1/5th of the data has to be processed.
The ExifTool Command Processor can show you all the data contained in your files. It loads the data directly from the file or the associated XMP sidecar file.
Before IMatch version 5.2.10 IMatch imported almost all metadata into the database, leaving out only some really large blocks like color tables, ICC profile data and other chunks of binary data.
In version 5.2.10, IMatch introduced the Tag Manager dialog and implemented additional rules to control which metadata is imported by default. IMatch now skips most of the camera-vendor and application-specific metadata, reducing the amount of data to store per typical RAW file by about 40%.
All metadata that is essential for IMatch's operation (XMP, legacy IPTC, EXIF, GPS etc.) is always imported and protected. You cannot prevent IMatch from importing these tags. But you can control all optional tags and tell IMatch which tags you want to include in your database. For this purpose, you use the Tag Manager.
The Tag Manager dialog can be accessed under Edit Menu > Preferences > Metadata 2.
The Tag Manager
When you open the dialog, IMatch analyzes the data stored in your database and then displays a list of tag groups and tags, and the number of data records stored for each group and tag.
Protected groups and tags are not displayed in this dialog.
When you click on a group in the list on the left, IMatch displays the tags in the group in the list on the right. You can either show all groups, or only groups which actually contain data.
Enable this option if you want to see only groups and tags for which there is actual data in the database. These are the tags and groups representing the metadata in your files. In this mode you can get a good overview about which groups and tags are filled with data, which of these are of interest for you etc.
Enable this to see the groups with the most data right at the top.
By default, this dialog displays localized group names and tag names - the same terms IMatch uses in the Metadata Panel and elsewhere.
To see the original group id and tag key, enable this option. This makes it easier to find groups and tags based on data shown by the ExifTool Command Processor or the ExifTool command line application.
Use the check boxes to include/exclude entire groups or individual tags. If a group is included, all tags in that group are automatically included. If a group is excluded, all tags in that group are automatically excluded. You can also include/exclude individual tags.
If you don't want to import data for a group or tag anymore, uncheck the group or tag in the list. IMatch then skips importing data for this group/tag, and the diagnosis removes the data associated with that tag/group.
If you want to import data for a group or tag, check it in the list. IMatch will then import the data associated with the group or tag in the future (for files added to the database, or when files are rescanned). To import the 'new' data for files already in the database, select the files in the database and reload the metadata.
Groups have an intermediate state (filled check box) to indicate that only some of the tags in the group are included.
When you click on the check boxes in the group list, you need to click twice to change from this intermediate state to the included or excluded state.
Modern digital camers literally write hundreds of data items to a RAW or JPEG file, usually in form of so-called maker notes. Most of this data is of no use for humans, but sometimes you might be interested to be able to see the values of some or more of these tags. Selectively enable the tags you are interested in in the Tag Manager and you will be able to display these tags like all other tags. IMatch also makes the data available via variables.
Another sometimes useful tag group is the 'Extra' group. It contains, among a lot of clutter, the UserComment tag which is part of JPEG metadata. Although this tag is not used by any major application, some older applications and devices use it to record some sort of user comment or other data. To see this data in IMatch, enable the Extra tag group and then the tags you are interested in - don't import the entire group because it often contains a lot of useless data which just fills up the database.
Close the dialog with OK to save the changes to the database. The Tag Manager summarizes the changes you have made:
When you exclude new groups or tags, IMatch does not remove the corresponding data immediately. The removal operation is performed when you run a database diagnosis. The new excluded groups and tags are in effect immediately for files you add to your database afterwards, or for files which are updated during a rescan.
When you include new tags to import, IMatch considers these new settings for all future metadata imports. If you want to import the data for files already in the database, you need to reload the metadata for these files, or force a rescan.
To do this, use the Rescan command and hold down Ctrl. Or use the Shift+Ctrl+F5 keyboard shortcut to get the Advanced Rescan options.
When you run a database diagnosis, IMatch checks whether superfluous data exists in the database. This is always the case when you have excluded tag groups or tags in the Tag Manager for which data exists. If this is the case, the diagnosis displays a corresponding dialog message where you can choose what to do:
You can remove the data (which is what you usually do) or skip the removal for this diagnosis run.
If you choose the don't ask again option, IMatch will not attempt to remove data until you again make changes in the Tag Manager. In this case the data stays in the database, but data for groups and tags you have excluded yourself will no longer be imported.