Translated from French (
viewtopic.php?p=170164#p170164 en français )
1 Metadata
Metadata can be added to photos to facilitate their management.
There are basically three families, from the oldest to the most recent: EXIF, IPTC, XMP.
The EXIF metadata are now reserved for technical information, it is logical not to modify them except for the dates and GPS coordinates which can be created or modified if necessary, using the menu "Metadata, Change timestamp" or "Metadata, Edit GPS data".
You can add a lot of information to describe, qualify, or organize and sort the photos, in the form of IPTC and XMP metadata.
The XMP standard tends to supplant IPTC, but one can continue to use these two families simultaneously.
The "
JPG" image format and some others support metadata embedded in the image file itself.
Other formats only support certain types of metadata, for example most of the "raw" formats only support external XMP metadata, put in a xmp companion file, next to the image file.
2 Keywords, categories, catalog
Keywords are metadata like any other, but XnViewMP has a specific tool called "Categories" to facilitate their management.
This tool also manages a database, "the catalog".
I use the term "assign categories to photos" to describe the action of linking a photo, a category and the corresponding keyword, which is done simply by checking a category box in the "Categories" panel while photos are selected.
In order for the "Categories" tool to write the keywords in IPTC or XMP format,
you must have previously validated the corresponding export options in the "Settings, Metadata" screen, otherwise only the "catalog" contains the categories linked to the photos, (in which case it is advisable to regularly make backup copies of the catalog, simply by copying the xnview.db file after quitting XnViewMP).
Note: it is mandatory to deselect the photos after checking the category boxes
There is a parallel between "categories" and "keywords": categories refer to the XnViewMP catalog and correspond to the keywords entered in the photos when an export option had been validated.
There are two other xmp metadata managed like the keywords: "Star ratings" and "Color Labels". This information is also stored in the catalog, and has its own export options in the same options screen, "Settings, Metadata".
3 Other metadata
The other metadata managed by XnViewMP are quite numerous; there is for example Caption, Title, Author, Credits, Locations ...
This other informations can also be written in the IPTC group and in the XMP group, but they are not managed in the catalog filter.
To write these metadata, select photos, then open the window "Metadata, Edit IPTC" (or Ctrl I). First you have to choose if you want to write "IPTC only" or "IPTC + XMP" in the
"Mode" box of the last tab. Then go through the other tabs and enter information in the fields, then click the write (or write all) button so that this data is written in the photos. In fact, only the "Caption" and "Source" tabs contain fields commonly used by amateur photographers.
Users with specific needs for using XMP metadata can instead use the "Edit XMP" window, which works similarly. One can also use the companion XMP files by having checked this option in "Settings, Metadata".
These various metadata are not managed in the XnViewMP catalog, but only written (or read) in the photos, which should encourage you to make backup copies of your photos if you were not already convinced of this necessity.
Reading metadata
XnViewMP can read existing metadata. First, enable metadata import options. (Only keywords, ratings, color label, and face tags if ticked will be read)
Then in Settings, Catalog, use "Import folders" button. This import reads recursively subfolders and builds the catalog.
4 Using Metadata : Filters
XnViewMP offers several ways to take advantage of the metadata you have added to your photos and the data that are mirroring some of them in the catalog.
- The "Category Filter" ("Catalog filter" now) panel allows you to find photos with a specific category. We can also say that the category filter allows you to find photos containing a certain keyword. It is an extremely efficient tool if you have filled in your photos with well-chosen keywords (categories), and possibly ratings (1 to 5 stars) or colors.
In the filter, with the Ctrl key you can select several categories, and with the Alt key you can exclude categories.
- The "Quick Search" box in the toolbar. This box allows you to quickly find a photo based on a criterion, but only among the photos currently displayed. The options are in
"Settings, Explorer, Quick search" the small magnifier drop-down menu (check at least IPTC and Catalog), This search is also about file names.
- The "Search" function in the Tools menu. This function is very rich, but searches for information in the catalog are much faster than searches for other metadata.
- There are also many methods of sorting and filtering photos in menus and toolbars.
All these methods make renaming or thematic storage of photos unnecessary. They also allow automatic display of captions or labels.
One should not confuse the storage of photos which can be simply chronological, and search, filtering, titling of photos photos which will be based on metadata, especially keywords.
5 Without metadata
For users who would like to use only the cataloging functions without any metadata, it is necessary to uncheck all the options in the settings > metadata screen.
This allows you to work on any file type, but limits you to using : Categories, Star ratings, Color labels, Tags.
And limits also the possibility to migrate to other softwares unless you know sqllite database management.
And remeber to backup your work sometimes by copying your xnview.db file, when XnViewMp is closed.
You can also export a xml file from catalog.(Categories pane > top right drop down menu > File's categories > export )
None of these links are broken. Same goes for the wiki: