Post written by Shelley Walker-Harmon, Gary E. and Carolyn J. Strong Special Collections Fellowship

“Have patience with everything unresolved in your heart and try to love the questions themselves” ~Rilke.

In my first post, I introduced the Potlatch aerial photograph collection and talked about why these photographs are compelling. This time, I want to get into the nitty-gritty: the more complicated and tedious part of the project. What exactly does it mean to organize thousands of aerial photographs?

The short answer is a lot of sorting.

When I first saw my workspace, a large table laden with unruly boxes stuffed with photographs, I had a very rudimentary understanding of what I was looking at. These were aerial photographs taken for the Potlatch Corporation, mostly documenting timberland in North Idaho. As I began sifting through them, I noticed they had dates, flight numbers, and photo numbers, and many of them were part of larger sequences. The problem was that none of those things were consistently present. They were mixed together, jumbled, weirdly numbered, and all out of order.

Here, as promised, is the behind-the-scenes how and why of organizing this photo collection.

Take Everything Out of the Boxes

The photographs arrived in nearly a dozen banker’s boxes, and the first step was simply figuring out what was there. There is a term I learned while doing this project: rehousing. I had to place all of these photographs into new, archival-quality folders. This meant physically handling each and every one of the prints, and even if each photo didn’t spark joy, they were all kept. Each image was fully placed into new folders, made of materials that would preserve them for the years ahead.

The individual photographs are not huge–approximately 9 by 9 inches–but there are many of them. Additionally, they are made of some hefty paper and weigh quite a bit! Some folders contained only a handful of photographs, while others held dozens. Depending on the thickness of the paper and the number of photographs in a particular flight, a folder might contain anywhere from roughly six to thirty images.

At first, it was tempting to think that organizing aerial photographs would be straightforward. Look at the number written on the photograph, put the photographs in numerical order, and move on.

But it became clear that there were some complications to this organizational approach.

The photographs had been accumulated over decades, and the information available on them varied considerably. Some photographs had extensive identifying information. Others had very little. Some had no obvious date. Some belonged to a sequence in which the first photograph–the one most likely to contain the identifying information–was missing.

Decode the Data

Aerial photographs often come with their own built-in numbering systems. In this collection, those numbers became some of my most important clues. A sequence might look something like: AB-1-1, AB-1-2, AB-1-3, AB-1-4, AB-1-5… That seems easy enough. But sometimes it looked more like: AB-1-1, AB-1-2, AB-1-3, AB-1-5, AB-1-7, AB-1-9…

Or a sequence might suddenly jump from photograph 5 to photograph 30. Then I wondered: are photographs 6 through 29 missing?

There could be another possibility: perhaps the photographer simply did not take photographs 6 through 29. Aerial photography was not necessarily intended to create a continuous photographic record of every square inch of land. A particular flight might have focused on specific areas, timber stands, roads, or other features.

Without more evidence, I could not always tell the difference.That distinction became an important part of the project. Rather than correcting the sequences, I recorded the gaps.

In the folder descriptions, I made notes about photographs that appear to be missing from a sequence. This preserves the uncertainty rather than turning an educated guess into an archival fact.

Some sequences skip only a photograph or two; others skip much larger sections. There are also sequences that alternate between odd and even numbers. In each case, I noted the apparent gaps rather than assuming that every missing number represented a photograph that had once existed.

Identify the Flights

The most useful organizing principle turned out to be the flight number.

Rather than arranging every photograph strictly by date, I arranged the aerial photographs sequentially by flight number within each year.

This made sense to me because the photographs were created as groups. A flight represents a particular photographic event: an aircraft went up, followed a particular flight line, and produced a sequence of images.

If I separated those photographs simply because their individual dates or labels varied, I would risk interfering with the original relationship between them.

The basic organizing rhythm became: Year, flight, photo number.

This sounds straightforward, but it was not always simple when I was staring at a pile of photographs with very similar flight numbers (PC-M-77 or PC-W-77, for example).

Flight sequence took priority over date because the flight number was a more reliable indication that photographs belonged together. When a date was provided, I generally assumed that the following sequence belonged to the same date unless another date was specifically indicated.

In other words, I was trying to preserve the logic of the original photographic project rather than impose an entirely new one.

A Wealth or Dearth of Information

One of the most interesting (and sometimes frustrating) parts of the process was discovering just how much information could be contained in a single photograph.

Typically, when the first photograph of a set was present, it might tell me things like the date, time, elevation, scale, lens information, and flight number. That information was extremely useful for identifying and describing the entire sequence.

But when the first photograph was missing, so was much of that information.

This created a recurring archival problem: how much could I confidently say about a photograph when the information that originally accompanied it is gone?

The answer in this case was only what the extant photographs allowed me to say. I made notes of the available information in the folder descriptions rather than filling in the gaps with my best guesses.

Interestingly, certain series were organized differently. Sometimes, identifying information appeared on the last photographs of each sequence rather than the first. This meant that the location of the data itself became something I had to keep an eye on as I worked through the collection.

I learned that archival arrangement can be less about following a single set of rules and more about adapting along the way, while being flexible within established guidelines.

Making Choices

Once I had worked through the photographs and identified the flights as best I could, I grouped the photographs into folders.

Each folder that I put together varies in the number of images it contains, depending on the thickness of the paper and the number of photographs in a particular flight. Within each folder, I arranged the photographs sequentially according to their flight and photo numbers.

The folder descriptions became an important part of this process. I included identifying information where it was available and made notes about gaps, unusual numbering, and other questions. I noted damage, annotations, and duplicates as well.

Often the foldering decisions were purely practical. I originally intended to keep flights separate in individual folders. However, some flights only had a few images, while others had close to 100. I settled on something that was based more on intuition: did the folder seem too full? Was it too thin? Could I split a flight into two or three groups and still have a healthy number of photos per folder? What was the most efficient use of space and materials?

Most importantly, my goal was to clearly document what was in each folder so that future researchers would be able to find what they were looking for. Something I took away from the project was the realization that an archivist’s job is not necessarily to solve every mystery in a collection. Sometimes the job is simply to make the mystery available for investigation.

Supporting Materials

I should also mention that photographs were not the only materials I had to work with.

Many of the documented years included a photo index. Photo indexes are maps with a grid overlaid on them, corresponding with the flight lines. These indexes are inconsistent and sometimes missing altogether. Some years have several indexes and maps; others have nothing beyond the photographs themselves. Some are large and complete; others are snippets cut out of a larger image. The indexes also use a variety of naming and numbering systems, which complicated matters when it came to confidently connecting a particular index to a particular series of photographs.

Initially, I had high hopes of mapping out each photo with each index. Eventually, I had to admit defeat as I realized the limits of what I could determine on my own. This kind of research is better suited to someone who is well-versed in GIS, or forestry, or ideally–both.

Still, the maps and indexes are important. They were intended to help identify and interpret the photographs. Matching them to individual flight series and then determining the location represented in each photograph was more complicated than I had anticipated. Reading an aerial photograph as a historical document is one thing; identifying precisely where that photograph was taken, using an old map and deciphering numbering systems with no key, is another.

To simplify the organization of the collection, I grouped all of the photo indexes together in Box 1, along with the other non-photographic materials, including reports, correspondence, survey certificates, and related documents. Researchers looking for an index or map will know where to start, even if the relationship between a particular index and photograph series is not yet fully understood.

What I Did–and What I Didn’t Do

By the end of the process, I felt satisfied that the photographs and supporting materials were organized in an intuitive and manageable way. That was my biggest goal. There are simply too many photographs in this collection for one person to completely decode every image, flight line, map, and numbering system in a summer. Instead, I focused on creating an organizational structure that would allow someone searching for a particular time and place to get started without having to sort through thousands of photographs themselves.

In that sense, the project was successful.

Archives are rarely finished projects. Organizing a collection does not necessarily mean solving every question it contains. Sometimes the most useful contribution is simply to make the materials accessible enough that the next person can ask better questions.

The Potlatch Aerial Photographs are now easier to navigate than when I first encountered them. The photographs have been grouped by year and flight, apparent gaps have been documented, and the supporting materials have been gathered into a location where researchers can find them.

The next step–figuring out exactly where all those little squares of forest are–is still waiting for someone else.