Digital History Blog

Review: Juxtapose from Knight Lab

You probably already know what ‘juxtaposition’ means. It is one of my favorite visual tools. When you set up a comparison well, this technique can demonstrate dramatic change in a powerful way. While juxtaposition is all about highlighting change, it requires some continuity. A consistent focal point helps viewers measure transformation. This aspect will come back into play later in my first digital history tool review.

Knight Lab’s Juxtapose, as the name suggests, juxtaposes two images by combining them into one. The tool is free to use. First, you upload two images, either with links or through Dropbox. Next, you add image dates and credits. There are a few simple options that you can adjust, but after previewing, you ‘publish,’ and voila, you receive a link and code for your Juxtapose. Now you can embed or share your new creation! Audience members simply toggle the slider feature, the single interactive element, to reveal more of one image and less of the other.

This is truly all the information required to enter into the interface to make your Juxtaspose.

That was easy! Or…was it? The first step that I listed, uploading two images, is not actually the first step. The process really begins with image selection. Let’s go back to my working definition of juxtaposition at the top of the page. The two images that you select should share a constant feature. 

I decided to select two maps of major roadways in Watauga County, North Carolina, from 1930 and 1968 because the official border of the county itself, as well as the location of towns within the county, provides visual consistency. That consistency is what makes the change over time accessible, measurable, and readable to viewers. (Side note: I got these images from the North Carolina Department of Transportation’s awesome historic county maintenance maps). In this case, we can use roadway maps to examine, perhaps, the state’s response to a growing automobile dependency, or the evolution of a rural landscape.

In order to connect to that consistency, however, we must manually resize images so that the county border and townships are congruent when the two images are overlaid. Juxtapose likewise recommends that “major [image] elements are in alignment.” That will take longer than you might have planned. Hand-drawn maps will never exactly line up, which frustrates a perfectionist (in remission) like myself, but I did my best to neatly align the borders and the location of municipalities. Tip: Juxtapose allows you to set the slider (default is at 50%), so I set the slider at a point where the borders overlap the closest; this can give your Juxtapose the illusion of congruence as viewers begin to play with the slider.

The juxtaposition is less effective when the county borders and townships, and thus roadways, are misaligned as shown here.

Now that we have a better understanding of the full process, let’s discuss pros and cons. 


As we have discussed, Juxtapose does not assist creators with the selection and resizing of images. In my map-specific case, I was forced to crop out important features, such as the compass and legend. Aside from being potentially frustrating and time-consuming, this process can also lower image quality. Additionally, because Juxtapose requires that you upload images through their URL or Dropbox link rather than a file, you may lose work over time due to broken links. 


On the viewer-side, the slider is easy to use and the finished product is attractive overall (if you have made the extra effort to resize your images appropriately). On the creator-side, the Juxtapose tool is responsive, requires little input, and intuitive—after I had saved another attempt at resizing an image and added it to my Dropbox, it took less than a minute to select, upload, and assess how my new image worked in the Preview window. I was able to successfully embed my Juxtapose (as seen below) using the HTML provided. I’m not ashamed to admit that I frequent help forums and YouTube tutorials whenever certain tech has left me at my wits end, but I simply had no need to do that here, it was just that easy. (Knight Lab does provide help for you if you need it, however).

Public historians may find Juxtapose a helpful digital tool that easily engages audiences. It can generate interest in any accompanying written content, particularly if you have noticed a lack of engagement with text posts. Alternatively, you can use Juxtapose as an effective and attractive means of presenting information on its own, thus requiring less written interpretation. If you go the latter route, you can add brief additional information about the images in the credits. I found powerful examples of its use for comparing two images of a single person, structure, or landscape, to illustrate transformation over time. Because the tool is easily grasped, educators could assign it for student use in projects.

What you get out of Juxtapose depends on what you put in. If you want to use this tool to demonstrate dramatic changes, then spend time with your images (selecting and resizing) to create a more effective juxtaposition. Aerial images (for example, Google Earth, as used in Knight Lab’s featured example) or images taken intentionally for comparison (for example, using an historic image of a house as a model of scale and perspective when retaking a picture of that same house) may work best. Ensure that your images are in a secure Dropbox and won’t be moved—to this point, you should periodically review your Juxtapose after publishing to check that your media is still up.

Here is the Juxtapose that I made, which I will call “Watauga County Road Survey, 1930 vs. 1968.” Use the slider to toggle between maps! Drop a comment below if you have used Juxtapose before with cool (or frustrating!) results or if this has inspired a new digital history project.

2 thoughts on “Review: Juxtapose from Knight Lab

  1. Collin, as a fellow perfectionist, the cons you listed were the exact reason I didn’t choose this program! That being said, I think you did an excellent job in creating a Juxtapose and explaining the different features! I know that this was a mapping assignment, but I have to say that I liked the other examples of people, monuments, and buildings better.

  2. Collin – very thorough review! Anyone who used this software would know what they were getting into based on your review. I wonder if to use this in the classroom it would be better for a teacher to set this up as an inquiry than to have students create something. I imagine this tool being useful for topics like urbanization or to view the impact of time on historical places, etc. I appreciate that the title rings true for what this software accomplishes!

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