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Many students ask me where I find the images used in my lectures, and how I go about putting them together.  Below I reflect on the practice of lecturing with visual materials, including the move from analogue to digital, the question of how I source images, and the ongoing relevance of the illustrated lecture as a pedagogical approach.





Lecturing is one among a range of pedagogies, and like all modes of learning it has both advantages and disadvantages.  One of the chief disadvantages (frequently overblown, I would argue) is that the lecture format often creates a passive learning environment, which results in reduced retention and comprehension.  Active and engaging lectures with frequent breaks, changes of pace and direction, student input and reflection, can dramatically improve the format. 


At its best, the lecture creates an environment of story telling, where the professor brings students along on a journey, encountering and interpreting materials together, making sense of complicated concepts, and integrating them into new ways of looking at the world.  As an undergraduate, I was fortunate to take classes with several master lecturers, including Gerald Early, William Gass, and Howard Nemerov.  As a graduate student, I was again fortunate to work with several excellent lecturers: Wendy Gamber, John Bodnar, and Henry Glassie--and to sit in on legendary lecture courses taught by David Baker (History of Jazz), Martha Crouch (Biology of Food), and David Pace (Paris and Berlin in the 1920s).


One of the chief advantages of the lecture format, of course, is the ability to survey visual, audio, and other materials, and to connect these to a broader story.  Photographs, paintings, maps, drawings, diagrams, architectural plans and elevations--the display of these artifacts expands the sensorial geography of the classroom, charges the story with new layers of meaning, and brings ideas to life.  This is particularly true for visual-spatial learners like myself.  Audio and kinetic images (film, video, data visualizations) only add further richness to the experience.


Thus, while I have worked to improve my craft in teaching, the use of images has become central to how I approach the lecture as a pedagogical form. 



Over the course of my working life as an educator, the technological enablement of the lecture has changed dramatically.  When I started teaching in 1998, we still used slide projectors (and grand viziers still issued edicts on papyrus scrolls).  The common practice at the time was to lash two slide projectors together in order to show images side-by-side.  It was a cumbersome apparatus that required a seldom-achieved grace in coordination.  But the projection of back-lit transparencies made lectures about architecture and cities come alive.  If our classroom did not have a dedicated slide projector, we lugged one with us.


The production, organization, tracking, and archiving of physical slides was a time-consuming process.  Many universities maintained slide libraries in their architecture schools and/or art history departments.  But when you needed a new slide, you had to make it yourself.  For many years I used a slide-making kit that I built for just this purpose, cribbing plans from a 1967 issue of Popular Mechanics.  It had a non-reflective white base with blue pencil grid, an adjustable standard with camera mount, and a dedicated single lens reflex camera.  To inspect individual slides, I used an old Argus slide viewer that I picked up at a garage sale in South St. Louis.  For awhile I developed my own slides, but this was time-consuming, so I sent the film out for processing.

Over the years, I built my own collection of thousands of slides, each one labeled, indexed according to archival standards, and stored in an old metal desktop cabinet.  The collection got so large that I had to create a database in Filemaker Pro to keep track of the individual slides and their contents.  To compose lectures, I spread slides out onto two upright light boxes (one for each projector), placed them in the proper order according to the outline, and then loaded them into the carousels.  For every lecture, I kept a record of the slide numbers and their order so that I could easily recompose the presentation.  For oft-repeated lectures, I simply made duplicate slides and stored them in a dedicated slide carousel--a dozen or more of which piled up in my office over time.



Needless to say, the production and use of analogue slides proved incredibly time consuming and labor intensive.  But the rollout of computer presentation software changed everything--um, eventually.  Many of us resisted the changeover because of the sheer effort it would take to create a whole new process.  But I finally made the jump to digital in 2007--the same year I switched to digital photography.  Of course Powerpoint had already been around for twenty years, and had become standard in the business world.  Academics were slower on the uptake (unsurprisingly); many of us did not make the change until our libraries stopped supporting analogue slide collections, and our classrooms ceased including slide projectors as standard equipment. 

Gone are the carousels, light boxes, camera stands, slide viewers, and other haptic artifacts of an antique process.  Now I use a Mac desktop computer loaded with Photoshop, Lightroom, Powerpoint, and other relevant software. With my Canon optical scanner, I can tear images from their object materiality and render them as digital files. Instead of hauling two carousels across campus like a chump, I carry a tiny jump drive in my pocket, or simply store the presentation as a file in the cloud.  Keeping track of images is made relatively simple by the employment of Adobe Lightbox, iPhoto, or any other comparable database.  Every image can be tagged with relevant metadata to aid in searching, sorting, and use.

Has the move from analogue to digital changed the quality of the results?  I would say yes, though not in any straightforward way.  Under analogue tech, I tended to be much more deliberative about the images; the costs of production in time and treasure militated against 'scattershot' collecting and hasty assemblage.  But while digital ubiquity tends to lead to collection bloat, the vastly increased pool means that I can more readily locate just the right image for a lecture on the Hanging Gardens of Babylon or the temples of Tenochtitlán or Urban Renewal in West Philly.  On the other hand, I find that digital projection lacks the luminosity and brilliance of the analogue; there is just something about forcing light from color transparencies through high grade plano-convex lenses that cannot be matched by digital rendering.  But the ability of digital projectors to display any signal sent to them--image files, movie files, web pages--has become indispensible to my teaching.







To be honest, I really do miss all those little cardboard widgets with their dark celluloid centers, so potent with possibility, just waiting for a flood of lamplight to throw their lush imagery onto the screen.  And the projection of two such images simultaneously onto two different screens made for high stagecraft and wonderful illustration.  However, I do not miss the hours upon hours spent keeping track of slides, making new ones, loading and unloading them.  Overall, I would say the digital switch has been a net positive for my work as an educator.



For my first job, I taught for two years as a visiting faculty member at Washington University (1998-2001).  My first course, "The Urban Crisis," was held in the auditorium of Busch Hall (left, top).  For lecture, we used two analogue slide projectors to show side-by-side images on two immense screens. 


The School of Architecture had a wonderful slide library that it shared with the Art History department, located in Steinberg Hall (left, bottom), and I was able to copy hundreds of the slides.  These images formed the early core of my collection, and I still use many of the today. 


In addition to the Washington University slides, quite a few images that I use in lectures are photographs that I have taken over the years, since I travel a lot.  I also have a personal collection of over 1000 postcards from the first half of the twentieth century that comes in handy.  And I have collected thousands of images over the years from archives, books, magazines, planning documents, and reports.  Friends and colleagues are also an excellent source for new images!  


Up until 2005, I continued to make analogue slides of images for use in lecture, but then I switched to all-digital format.  To facilitate the shift from analogue to digital, I purchased two converters that could scan each physical slide and render it as a high resolution jpeg file.  My unfortunate graduate assistants spent many hours on the conversion process!


Since then I have collected thousands more images as native digital files from the interwebz, usually found through searches.  When I conduct a search through an on-line engine, I always restrict parameters to non-commercial sources and high resolution images.  Anything smaller than 1900 pixels on the long side does not project well on a large screen.  Some professors leave the sourcing of images to their graduate students, but I am very particular (some would say obsessive) about the content, resolution, and tone of the images that I show. 


Still, beyond conducting 'global' searches, there are a few sites that I go back to repeatedly, a list of which I include here.



Rifling through thousands of images and distilling down a small collection for use in a lecture can be a time consuming process. This was particularly the case when using analogue slides. Fortunately, in this digital age, keyword searches through titles and metadata make finding the right image much easier.

In building a lecture, I begin with an outline of what I want to discuss.  I never write out lectures verbatim, and over time I tend to internalize the outline and use the images as narrative cues.   Once I have created an outline, I then recruit images to illustrate key points or to provide prompts for delving into particular concepts.  I apply text sparingly, either to frame the discussion with keywords or to annotate an image with crucial information.  An overload of text can kill a lecture.


Of course, an overload of images can also be a problem, leading to visual fatigue among students.  I find it useful to edit the content of the lecture and to focus in more depth on fewer images.  At first, this proved painful, as it challenged my obsession with 'coverage'--the drive to account for everything.  How can I possibly teach about the development of cities without discoursing on the Coliseum, the Parthenon, the Hanging Gardens of Babylon, the Crystal Palace, and the Reliance Building? How can I teach urbanism without an entire lecture devoted to Hausmann?  The problem was twofold: I struggled to cover the greatest hits, and the greatest hits themselves came bundled in highly problematic narratives that privileged 'Western' origins and views.


Eventually I abandoned 'coverage' as a hopeless cause, and now tend to use fewer examples for richer, more nuanced effect.  Importantly, these are not always the most 'iconic' buildings or landscapes; often times I employ the wisdom of the great archaeologist James Deetz to give way to those "small things forgotten."  After all, 'official' planners account for only a small portion of the story of cities, architects even less so.  Now I am much more likely to lecture on Istanbul's water wells than on Sinan's grand palaces; more likely to focus on the Hutong house than the Forbidden City, more keen to discuss the chinampas of Xochimilco than the great temples of Tenochtitlán.  In other words, my lectures are weighted less on high architectural achievements (though these certainly make appearances), and more on patterns, emergent built forms, and processes of city-making.  If Henry Glassie taught me anything, it is that big stories can be told through humble objects.  


In terms of rights and attribution, I follow the College Art Association Code of Best Practices in Fair Use for the Visual Arts.  The code spells out terms for the use of images in a range of formats, including print and on-line publications, conference presentations, student work, and classroom lectures.  The CAA's position is that "teachers in the visual arts may invoke fair use in using copyrighted works of various kinds to support formal instruction in a range of settings, as well as for uses that extend such teaching and for reference collections that support it, subject to certain limitations."  The limitations include the following points:


1. The works selected should further the teacher’s substantive pedagogical objectives.


2. Student access to course management sites where such works are made available

     should be restricted to those enrolled in the course.


3. Images made available to students should, to the extent possible, accurately

    represent the works they depict.


4. If providing downloadable images is justified by the teacher’s objectives,

    these should not exceed a size required for display on a personal computer or mobile device.


5. When displayed, images should be accompanied by attribution of the original work as is customary

     in the field, to the extent possible.


6. Images and other items in a reference collection should be augmented with appropriate and

    reasonably available metadata.

The one point where I diverge from CAA best practice is in noting sources on the displayed slides.  I find that this creates a distraction from the purpose of the illustration.  Instead, I note the source / creator of every image in my own records or in the metadata of the image file.


In short, the images that I show in the lectures come from multiple sources over time, some born analogue, some born digital.  I recruit some images from my own private collection, and some from archives and other institutional sources.  Some images I have had for 20-plus years, others I might have downloaded last week.  In all cases, the use of images can dramatically enhance learning in courses on architecture, urbanism, and cities.

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