The following piece was originally prepared on for Web site of the American Society of Picture Professionals (ASPP) and was available on that organization's site for about a year. As, after a reorganization of the ASPP site, this text was no longer available there, so I decided to make it available on my own site. (It is now again available on the ASPP site, also.)

The following is a brief overview of concepts presented in much more detail in my (out-of-print) book, Organizing Your Photographs. While primarily addressed to stock photographs, the concepts are applicable to all types of image collections.

Image Numbering, Filing, and Retrieval

By Ernest H. Robl
© Ernest H. Robl 1998
All rights reserved

Introduction

Stock photographs need a unique identifying number for several purposes:

• To retrieve an image from a file
• To uniquely identify which images are submitted to a client or returned by a client
• To uniquely identify which images are licensed for use by a client
• To determine where a particular image is to be filed (or refiled when returned by a client)
• To link to additional information about an image (Even when caption information is printed on a transparency mount, additional information may be on file elsewhere or may be provided to a client on a separate caption sheet.)
• To link to other documents related to the image, such as model or property releases

Unique numbers for images facilitate and simplify communication about the images.

Identification numbers are related to, but somewhat independent of cataloging of images, which provides subject access to images through an external tool, such as a text-based computer database. In other words, you can use various combinations of image numbering and cataloging systems, with use of one not necessarily dictating use of the other.

Assumptions

The following comments assume that you are working with 35mm transparencies (the most common format for stock photography) and that you have available or are considering use of a computer for at least some aspects of managing your image collection. A computer is not absolutely necessary but certainly simplifies many areas of working with large volumes of data.

Options

You have two basic options for assigning numbers to photographic images in your collection:

• Use classification numbers: The number is based on subject content.
• Use accession numbers: Numbers are assigned sequentially as new material is added to the collection.

Both systems have advantages and disadvantages, as discussed in the following sections.

Classification systems

Classification systems subdivide the world into a few large subject categories and then successively redivide each of these categories again and again. The Dewey Decimal (and related Universal Decimal) and Library of Congress call numbers used in book libraries are examples of classification systems.

Advantages

The main advantage of a classification system is that similar subject material is filed together. However, this benefit may be more than offset by a long list of disadvantages (at least for small collections).

Disadvantages

• Trying to build a classification system on your own is a huge amount of work; implementing one designed by someone else takes a lot of learning -- and, in some cases, requires purchase of expensive reference materials..
• The classification system is not sufficient to uniquely identify items if you have multiple items with the same same subject. Then you need item numbers added onto the classification. (You do need distinct numbering for circulation purposes -- tracking what's in and what's out.)
• The combination of classification and item numbers can make for very long identification numbers. The longer the numbers, the more likely you are to have transcription errors in documentation or filing errors.
• In a classification-based filing system, your collection grows from the middle out. Instead of simply adding on a new filing cabinet, you are constantly shifting and re-arranging your collection as new items are added throughout.
• The more specialized a collection is, the less useful a general classification system is. (For example, if your entire collection consists of photos of butterflies, using a general classification system designed by someone else, each of your classification numbers would begin with the same -- probably lengthy -- prefix.

The biggest problem, however, is that most items (books, photos, etc.) fall into more than one subject category, but each item can only reside at one classification location. For example, you have a photo of [famous person] at [famous landmark] doing [strange activity] at a meeting of [large national organization] on [special holiday]. Under which do you file it? You may need to retrieve by any of these or even additional subjects. (Cataloging solves this problem, but is beyond the scope of this article.)

Accession numbering

Accession numbering is simple and easy to implement, though it still requires some application of judgement.

Advantages

The main advantage of accession numbering is its ease of implementation.

• Use of the system does not require any advanced knowledge or design of a complex system.
• Filing and refiling of items takes a minimum of effort.
• Numbers are typically short, consisting of six to eight digits, which reduces transcription errors and filing problems.

Disadvantages

The main disadvantage of accession numbering is that the numbers do not contain any subject information and images of the same subject and of related subjects may be found at many locations throughout the file. However, all of any given shoot should still file together, which may not be the case with a classification system.

Implementation

Numbering items by film or in the exact order that they were shot usually does not make sense because (1) professional photographers frequently shoot with more than one camera body at a time, and (2) for later review later review, a more logical grouping is preferable.

Therefore, use the following sequence for each shoot:

1. Do an initial edit to discard images not worth keeping. (Remember, storage space costs money.)
2. Edit the remaining images into a logical grouping.
3. Now, apply the image numbering.

Options

You have two basic options in applying numbers:

• Make the numbering totally sequential (The first image is item 1, and numbers increase from there.)
• Use some type of prefix, such as the year

Except for collections which want to conceal the year that a given image was made, the second option is preferable for the following reasons:

• You may be starting with a collection that already contains images that cannot be immediately numbered, but with the year prefix, you can begin with organizing images from the current year -- and later go back to earlier material.
• A totally sequential numbering system shows how many images you have in your collection. Submitting images numbered 51-57 may leave the wrong impression with a client.

A six-digit numbering system, using YYnnnn (where YY are the year and nnnn is the sequential number) should be sufficient for most collections. You can easily purchase numbering stamps for stamping the identifying numbers on the transparency mounts. A four digit sequence for each year lets you add 9,999 images per year to the collection. (Even if one or more photographers shoot more than this, it is unlikely that you will want to retain all of these images.)

For small cooperative agencies, preceding the identification with the photographer's initials may be sufficient to produce unique identification numbers for each image.

If you also produce images in another format, such as 6x6 cm transparencies, you may want to apply a separate sequence for these images. For example, 35mm transparencies start at 970001, but the 6x6 cm transparencies start at 979001. This split lets you add several thousand 35mm transparencies and 999 6x6. Depending on the amounts of material in various formats, you an adjust the starting number for each sequence before you implement the system.

Considerations

For image collections, determining what type of numbering and identification system to use must also consider the physical methods of storing the images and whether multiple types of image formats need to be handled:

• Do you create (or handle) only 35mm transparencies?
• Do you also need to handle larger transparency formats?
• Do you also have negatives and prints that need to be filed and retrieved?
• If you have multiple formats, does it matter to you whether the different formats are filed separately or together?

Photographers who do not already have a numbering system and who work with a stock agency should consult with the agency to see what type of identification system the agency uses. However, keep in mind that the agency may have quite different needs from an individual photographer, and, if you work with several agencies, you probably cannot make your system compatible with that of all the agencies.

Storage

For 35mm transparencies, you have two basic options for storage:

• Cabinets with shallow drawers, in which groups of transparencies are filed. (These groups can be pulled and reviewed on a stack-loading viewer.)
• Regular file cabinets in which slides are stored in slide sheets. (The content of these sheets can be reviewed on a light box.)

  An advantage of the second method, slide sheets, is that different picture formats, even negatives, can be combined in the same file. Consider, however, whether you really want negatives intermixed with your transparencies, as they are handled quite differently.

  With negatives, you typically want to leave films intact as much as possible, cutting the films into strips that fit sheets. Writing identifying numbers on negatives is difficult or impractical. Therefore identification numbers for negatives typically consist of a film number, recorded on the negative sheet or other container, and a frame number already imprinted on the film.

Duplicates

Duplicate transparencies present a special problem. You may choose to file these as either

• A part of the main filing sequence, in the same location as the originals
• A part of a completely different filing sequence, at a different location

In either case, the number of a duplicate transparency should indicate it is a duplicate -- and provide a reference back to the number of the original.

My own choice, because I normally have only a small number of duplicates to deal with (typically only for situations where I self-syndicate a travel piece with illustrations to newspapers), is to use a one-digit suffix (which is actually a separate field in my computer database). This lets me file duplicates with the originals.

Transparencies without the suffix are originals. Transparencies with the suffix are duplicates. So, 970027 is an original; 970027-1 and 970027-3 are duplicates of 970027. If you typically deal in larger numbers of duplicates of each image, use more digits for the suffix.

Final thoughts

Keep in mind that you are not the only one using your identifying numbers. Your clients will also be using these numbers to track your work. If you use an overly-complex system, you are making life more difficult for your clients. In fact, the clients (or your stock agency) may have a limited number of characters in their image-management databases for the photographer-assigned number. If the number is too long, it will not fit.

On the other hand, six and eight-character numeric stamps are readily available at most office-supply stores.

Keep it simple.

More information

For more information on the concepts discussed here, see my book, Organizing Your Photographs (Amphoto, 1986). This book is out of print, but should be available from most larger libraries. (If your library does not have a copy, it can probably borrow a copy from another library through inter-library loan.) The chapters on computer use are dated now, but other information is still relevant.

Ernest H. Robl is a North Carolina-based photographer and writer who specializes in travel and transportation stock subjects, particularly railroads. In the past, he has worked in various positions for the Duke University library system, including as a cataloger, a supervisor of other catalogers, and as a system manager for a large multi-user computer which operated the library's on-line catalog. For additional information about Ernest H. Robl, see the Business section of this site.

Additional essays about photography are available at the
On Photography section of this site.

To view sample images by Ernest H. Robl, go to the Pictures by category page.

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