DAM Building Blocks Part 2


This is the second part of a series and focuses on filenaming for DAM systems.

What’s in a Name?

With modern Digital Asset Management systems, file names need only serve a singular purpose — providing uniqueness. By that , I mean that each asset should have a file name that is distinct from any other content of the same type. Other than that, most of your users will not give filenames much thought, even though they are used for storing, organizing, and retrieving their own files, or those in the DAM. For organizations, however, there is another consideration — assuming that images will be coming from different computer file systems — which is to pay attention to the different restrictions on filename lengths and what characters/symbols are allowed.

For individuals, a systematic way of naming files will help you to track your images. If you intend to share your digital image files with others, then it’s critical that your filenames be understood by any potential computer systems on which they are shared, not just your own.Organic Orange Showing How File ID's Give a Clue as to Class

While file names and/or numbers like SKU, Dewey Decimal or ISBN numbers may  have a method behind their madness (like all produce in your supermarket that starts with a 9 in it’s SKU signifies that it’s organic), it is not necessary for a filename to carry any other information about an image. This is what your DAM system is for; the filename is simply the hook that you use to hang all the rest of the information on that you want to store.


What “Is” in a Name?

At minimum a file name should:

  •     Distinctly identify a specific file (at minimum within a particular content type).
  •     Allow you to move/transfer the file to another computer systems without changing the name.
  •     Give you some idea of what type of content it contains (typically this is done via the three or four letter extension that follows the period.

For individuals managing their own files, only the first item above is mandatory.  A filename ensures that there is only one item with that name within a DAM by providing a form of unique identification ( or [UID] ) for each digital “asset.”  In workgroups or organizations, you want each of your assets to have a unique name/number so there is no confusion when you refer to an item.

Having a unique names will also prevent accidental overwriting of any file. No existing operating system allows you to store two files of the same type (using same extension) and same filename in the same location If you move or copy a file from one folder/directory of a hard drive, CD-ROM, or other media storage device to another where a file with the same name is already located, the new file will either replace the file in the destination folder, or it’s name will be modified automatically by the system to prevent this from happening.

Most photos from digital cameras will be automatically named with a 4 digit number, often preceded by IMG or DSC — like “IMG_9007.JPG” — to note that these are images. In an organization with more than one camera of the same type, it’s a sure bet that there will be numerous images with the same filename that may be added to the DAM system. So renaming to ensure uniqueness is a key first step.

Using a short sequential number might not seem to be unique. However, combining this number with another variable or two can ensure uniqueness. For example,post office boxes that only have 3 numbers could be confused with those at another physical location. However, using the name of the town or the ZIP Code of that post office as well as the box number makes it distinct and insures that mail gets to the right recipient.

Post Office Box as Metaphor for Unique NamesPotential File Name Schemes

Some DAM software may have the means to create numbers or sequences and automatically increment items as they a brought into the system. Some of the more popular accession schemes include : number order, date-based, date plus (file type or number sequence), or date/time. Other options include subject-based methods which also require a sequential number or letter to ensure that each name is unique (in the examples below, I’m using the generic “.ext” to note the filename extension, in use this would be something like .jpg .mp3, or .ppt).

  • Number-based: Unique job assignment number followed by two or three digit sequence number, example: 1789-001.jpg
  • Date-based: YYMMDD, or YYYYMMDD followed by a three digit sequence number, such as 080324_123.jpg, or 20080324_123.jpg
  • Date +: YYMMDD, or YYYYMMDD plus NEF or CRW plus a sequence number, such as 080324CRW123.jpg, or 20080324CRW123.jpg
  • Date/Time: date in the form of YYMMDD followed by the time in the form HHMMSS and a one to three digit sequence number, such as 080324_092315_123.jpg, or 20080324_092315_123.jpg
  • Subject based: two or three letter alpha code for subject, followed by five or six-digit sequential number, such as ag006126.jpg

Expert Tip: Back-up File names in the File Itself

For those files that allow for embedded information you can also “back up” many or all of the information about an asset within the asset itself. At present it’s possible to store information within a variety of image, audio, video and document files. This can be useful when migrating from one system to another, or when sharing files with others outside your organization.

Those unfamiliar with how Digtal Asset Management software works may try to make a filename more descriptive than it needs to be. However if you are building a DAM with other people’s assets then you’re likely to start with files that have been named in a variety of “creative” ways.  In order to standardize and follow best practices in file naming, your first inclination is probably to rename them. However, before doing so, you may wish to store the original file name as a metadata value – within the file itself. This means that the original owner will still be able to search for it in the company DAM using their familiar name.

See the other tips at the end of this article for ways this can be done.



Don’t Forget the File Extension

If image files will never be shared with others, then the only limitation is whatever is imposed by the specific operating system. For instance, while it’s not required for a file name to have an extension within the Mac OS, doing so means that you can co-mingle files of different content types within the same folder. For instance, if I have a WAV audio file that was made at the same time as an image, I can place drp13010390r.wav along with drp13010390r.jpg without a problem.

If the content are not related (like the example above), using the same name before the extension is likely to cause confusion in the future, so it is probably best to avoid that situation.

File name extensions are used to identify different types of content in a Digital Asset Management system so that the OS knows which application to use when you start to open that file (Windows operating systems require an extension in order by default). If you can see the specific “extension” used on the file, you may be able to tell at a glance whether it’s an image file (.jpg or .tif); audio file (.mp3 or .wav); document file (.doc or .pdf), or video file (.mpg or .mov). Exactly what is in that image or video may not be clear until you open it in the appropriate viewer, though the file name before the extension may give you some hints.

One university currently has their photographers upload their images to their online DAM via a web interface. They ask each to rename images so that they include a descriptor, date, and sequence number; like mbagraduation-20120612-001. The combination of all three variables ensures that the file names are unique within their own system. However this doesn’t necessarily give them a uniform look as the descriptor that is used may vary in length.

The Length & Special Characters used in File Names is Important When Sharing

As different file systems (Mac, Windows, Unix/Linux) may impose different restrictions on the maximum file name length and/or the types of characters that can be used; it’s usually best to establish some minimal best practices. Since the files from your DAM are likely to be downloaded by your users and exchanged with other colleagues (often using different computer operating systems), you need to be aware of filename limitations to ensure maximum portability for cross-platform compatibility.

For example, while you can create a file name like abc123.tif on a Mac, that back slash ( ) can’t be used if the file is moved to a Windows machine, as it will be interpreted as a directory or folder level.  Other forms of non-alpha-numeric punctuation such as / : ! @ # $ % ^ < > , [ ] { } & * ( ) + = may have specific uses with various operating systems and create confusion or errors. Even something as simple as a blank space in a file name can create a problem if placing image files on the web. For example posting a file such as “company logo.jpg” will cause many systems to automatically insert something like “-“ to fill in the blank space changing the filename to “company-logo.jpg” which can be quite confusing if someone is searching for that file in the organizations DAM.

The Universal Photographic Digital Imaging Guidelines (UPDIG) site has a nice short list of filenaming recommendations.

Filenaming Conventions

If you don’t have any specific ideas on how you wish to name your files, you might start with this article I’d written that discusses considerations in creating file naming conventions.

The North Carolina Department of Cultural Resources has an great four part video tutorial series on file naming that covers a number of issues.

Once you do have a system in place, consider writing up your file naming convention as a standard that everyone can use to give some uniformity to the assets in your DAM system.

Future Proofing Your File Names

There are a number of ways to store the original users image file name for future purposes, though the technique and field used will vary by content/file type. I’ve outlined how to do this with a number of image browser and single-user image database/cataloging applications for digital image files in the Filename 2 Title article.

Which field to use for final storage is up to you, but you may want to do some checking to make sure it’s a field that can be searched for in the DAM system you choose. I make it a habit to use the IPTC:Title field as it’s widely supported and included in the older form of the International Press Telecommunications Council's metadata schema which is synchronized with the newer IPTC Core form. When it doubt stick with these better known fields, or use the Keyword field, as this is one of the few fields that treats each keyword as a discrete entity.  If you aren’t familiar with terms like IPTC and Exif, don’t worry. I’ll be addressing those “Standards” in the next part of this series.

If you are starting with a large number of files for which you need to assign unique names, there are applications that can make this renaming process a bit easier. Many applications can use discrete values that are already in the files, such as the Title of an MP3 file, or the “Date Captured” value from the Exif metadata of a digital camera file. These values can be combined with others to ensure that each file has a name that is different from all the others in your system.

One of the more popular that is available for both Mac and Windows platforms  is A Better Finder Rename or ABFR for Windows. Unlike some of the freeware programs ABFR can pull in information from the embedded metadata in files, such as Exif data from digital camera images, or ID3 data from audio files, and has extensive options for batch processing, adding sequential file names and even regular expression substitution.

Some DAM software applications have a renaming feature built-in, and can change the name of a file as it is added to the system. If you choose to go that route, be sure that it works the way you expect and that you have a backup plan in place in case you decide to migrate from that system in the future.

I hope that gives you a better understanding of the importance of file names within a DAM system. If you have questions or comments, please feel free to add those in the comments below, or in a note to the Dam Coalition, or my Twitter account.

Back to Part 1: DAM Building Blocks

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