User Guide

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What is Civil War Photo Sleuth?

Civil War Photo Sleuth is a free website that allows users to add, find, and identify photos of soldiers, sailors, and civilians from the American Civil War era.

What is the mission of Civil War Photo Sleuth?

Our mission is to rediscover the lost names and stories of every photo of American Civil War soldiers and sailors. Tens of millions of portraits were created during the war, and millions survive today, but only an estimated 10 to 20% are identified. We have our work cut out for us. But with your help, we can do it!

You can read more about our mission and vision in this article in Military Images Magazine.

What can I do to help Civil War Photo Sleuth?

There are many ways you can help!

  1. Add identified and unidentified reference photos to the database. You can add digitized photos from your own collection, or from any of the digital archives listed on the Resources page.

  2. Add tags about a photo’s format and photographer and the subject’s uniform to help describe photos in our database to make them more searchable and easier to identify.

  3. Propose identities for unknown photos in our database.

  4. Verify (or debunk) identities of unknown photos proposed by other users by voting on them.

  5. Categorize the sources used to identify photos to help determine the quality and reliability of the identifications.

How much does it cost to use Civil War Photo Sleuth?

CWPS is completely free to use. We hope to keep the core features of CWPS free for all users for the long term. This creates as few obstacles as possible for people to contribute photos and information to the site, which is our main goal.

How is CWPS funded?

Because we hope to keep CWPS's core features free for all users, we are currently funded by a combination of public grants and private individual donations. Our primary financial support comes from the National Science Foundation and Virginia Tech.

We do not sell user data or display advertisements. This is similar to the financial model used by Wikipedia.

If you would like to support CWPS financially, please see donation instructions on our Donate page.

What technologies are being used by the project?

CWPS aims to bring Civil War photo enthusiasts together and provide them access to cutting-edge technologies and customized resources to support their research, including face recognition and crowdsourcing.

CWPS uses state-of-the-art face recognition technology from Microsoft Azure. When a user uploads a photo, the software tries to detect the soldier’s face, analyzing dozens of unique reference points per face (called a “faceprint”), and compares the points against tens of thousands of identified photos in our archive. Face recognition allows us to find matches even when the soldier’s facial hair changes, or if a different view of him is in our archive.

Beyond face recognition, CWPS also takes advantage of the latest crowdsourcing techniques. Crowdsourcing involves dividing up complex work into small “micro-tasks” that can be completed online by many independent workers. Because automated facial recognition is still imperfect, we can complement the computer-generated results with crowdsourced human judgements.

If I have two photos, can Civil War Photo Sleuth tell me if they are the same person or not?

Unfortunately, probably not. It turns out humans are still better than cutting-edge face recognition for deciding between two close matches. That's because humans can consider physical features that face recognition ignores (like hair style or ear shape), as well as broader context like where the unknown photograph was taken and what uniform the soldier is wearing. Face recognition, on the other hand, is great at narrowing down thousands of possibilities to a shortlist of a few dozen, so that's the primary way CWPS uses it.

What data sources are being used by the project?

The digitized photos in our reference database come from a huge variety of public and private collections. These include the Library of Congress, National Archives, US Army Heritage and Education Center, National Portrait Gallery, and many others. Many users have supplemented these public collections with photos from their private collections.

For military records, our users frequently consult the National Parks Service Civil War Soldiers and Sailors Database, American Civil War Research Database (subscription required), state archives, and other key sources.

Please check out our Resources page for links to digital archives with Civil War photos and information.

Where can I learn more about CWPS?

To learn how to use CWPS, please visit the links in this User Guide. The “Getting Started” tab has short videos of all the major features.

To learn about the research behind CWPS, please check out the publications in the “Research” section of the About page.

Who is behind Civil War Photo Sleuth?

Please see our About page for more information about the Civil War Photo Sleuth team.

Why are you doing this?

We are passionate about American history and believe it is important to remember the causes, events, and consequences of the Civil War. We find photos to be especially compelling evidence of the war's participants and their roles. We share the goal of our partners at Military Images to "showcase, interpret and preserve these rare images."

CWPS is also a research project led by Prof. Kurt Luther at Virginia Tech. We are seeking to invent new ways to use crowdsourcing and computation to promote historical education, preservation, and research. You can read more about our research on the About page.

How can I contact the team?

You can leave feedback using our Feedback Form. You can also email us at