How to Set Up a Catalog Numbering System

Last week we looked at how to catalog your collection and the software available to do that. This week, we’re looking at how to set up a catalog numbering system and the kind of information we want to prioritize in our collections, whether it’s for our own personal reference, for other people to use after we’re gone, or insurance purposes.

Catalog Numbering Systems

If you’ve ever visited a library—I am assuming everyone has (if not, go to a library!) —you’ve no doubt seen a very prominent numbering system in use. The Dewey Decimal system allows libraries to organize and catalog books using a numeric code. Each prefix in the string of number indicates what subject matter the book relates to. Additionally, each call number has additional numbers indicating where the book falls in relation to that subject and author information. All of this is contained in a simple numerical code! The Dewey Decimal system dates back to 1876, and although it has been updated over the years, it is still in use in libraries today.

If you visit a museum, you may see a similar string of numbers on various artifacts. Sometimes the numbers are also included on the signage within the exhibits. These catalog numbers are very similar to the call numbers on books in libraries, however, there is no standard in catalog numbers that is used by all museums. Typically, these numbers will be in a trinomial system, which each section representing a specific data point. For example, a catalog number of 2024.003.0001 would be broken down into: 2024 meaning the year the item was acquired, .003 indicating it was the third collection of items to be acquired, and finally, .0001 would mean that this object is the first item in the collection. For a museum that routinely acquires donations of materials this system works very well. For a private collector, who is acquiring items often one or two pieces at a time, this may not work as well, as the number of collections (middle number) in any given year could grow very large.

Therefore, it may be more reasonable to modify this number system and use the middle number to track the source on a market basis rather than by individual person. For example, using the same number 2024.003.0001, the first number would still represent the acquisition year, but .003 would now represent “eBay,” and .0001 would represent the first item purchased from eBay that year and added to the collection. In this system, you may have various numbers that would retain the same meaning regardless of the acquisition year.

2025.003.0013 would simply mean the item was acquired in 2025 from eBay and that it is the 13^th item from eBay that year. Your additional secondary numbers could represent donations, garage sales, specific auction houses (Fleischer’s, etc.) you regularly purchase from, and individual people you regularly trade with, or from whom you have received a large collection.

• .001= Donations/gifts
• .002= Garage sales/flea markets
• .003= Ebay
• .004= Fleischer’s
• .005= Joe Smith

Once you have this key, it is easy to add more numbers to it as you go if they are needed. If you start buying a lot of items from another auction house, for example, then you simply add that new venue in as .006.  The rest of the system stays the same, as the first number is always the year of acquisition, and the last number is always the number of the individual item.

Is everyone still with me? I know this is a lot of numbers and may seem convoluted, but the nice thing about having a system like this is that it gives you a good amount of information by just glancing at a number. This is especially useful if you do not have a computer-based system and are looking up items by hand in a notebook or with an index card system. Knowing that the item you are trying to find was purchased on eBay in 2023 gives you the first two numbers and narrows your search. Likewise, if you are looking at an item in your collection and see the catalog number for it on a tag with it, you immediately know where you got it from and when. If you need some examples of what the secondary numbers can represent, take a look at the Research Arsenal database search page and select “Search by Source/Call Numbers” then select “11th OVC Archives” from the top drop down menu. Once you select a year, you’ll be able to select the secondary set of numbers and can see how those work to filter through collections on the database. We’ll go into how to tag objects and archives in the next post as that can get a bit more complicated.

Now, as an aside, there are situations where these numbers may change a little. Let’s say you have a Civil War letter and the corresponding envelope. Or a letter and the CDV the soldier sent home with it. Obviously, these two items are related, and they also came together. This is the key part—they CAME TOGETHER. From a catalog standpoint, these would be cataloged as a single item. The envelope is intrinsic to the letter—it was not mailed without the envelope; the envelope is part of the overall object. The CDV was mentioned in the letter and mailed with it, therefore, it became part of the object of the letter. In this case, there are a couple of options of how to handle this. You would use the same numbering system we discussed above with just a minor addition to indicate they are tied together. Personally, I use lower case letters, so the letter would be 2024.003.0012a, and the envelope would be 2024.003.0012b. I prefer lower case because at times a “B” can look like an “8” very easily depending on handwriting, and there are less issues of that with lower case letters. If you prefer to use strictly numbers, then you could structure it as: 2024.003.0012-1 and 2024.003.0012-2 or use only decimals with 2024.003.0012.1 and 2024.003.0012.2. This really just comes down to personal preference. To me, using extra numbers at the end makes it easy to not see a decimal point or a hyphen and then get .0012.1 confused with .00121. This is why I prefer using letters to indicate items that are tied together.

For our next blog post, I’ll discuss how to label your items with catalog numbers, now that we know how to create a system. In the meantime, go through your collections and determine what your secondary numbers might be. Find out where you’ve acquired a lot of your items and use that as a guide to create those prefixes. Once you have that, save that as a key and use it to reference and add more numbers to as your collection grows.