Digitization Details: Bringing Duke Living History Into Your Future

Recently, I digitized 123 videotapes from the Duke University Living History Program. Beginning in the early 1970’s, Duke University faculty members conducted interviews with prominent world leaders, politicians and activists. The first interviews were videotaped in Perkins Library at a time when video was groundbreaking technology, almost a decade before consumer-grade VCRs starting showing up in people’s living rooms. Some of the interviews begin with a visionary introduction by Jay Rutherfurd, who championed the program:

“At the W. R. Perkins library, in Duke University, we now commit this exciting experiment in electronic journalism into your future. May it illuminate well, educate wisely, and relate meaningfully, for future generations.”

Clearly, the “future” that Mr. Rutherfurd envisioned has arrived. Thanks to modern technology, we can now create digital surrogates of these videotaped interviews for long-term preservation and access. The subjects featured in this collection span a variety of generations, nationalities, occupations and political leanings. Interviewees include Les Aspin, Ellsworth Bunker, Dr. Samuel DuBois Cook, Joseph Banks Rhine, Jesse Jackson, Robert McNamara, Dean Rusk, King Mihai of Romania, Terry Sanford, Judy Woodruff, Angier Biddle Duke and many more. The collection also includes videotapes of speeches given on the Duke campus by Ronald Reagan, Abbie Hoffman, Bob Dole, Julian Bond and Elie Wiesel.

residue
Residue wiped off the head of a U-matic playback deck, the result of sticky-shed syndrome.

Many of the interviews were recorded on 3/4″ videotape, also called “U-matic.” Invented by Sony in 1969, the U-matic format was the first videotape to be housed inside a plastic cassette for portability, and would soon replace film as the primary television news-gathering format. Unfortunately, most U-matic tapes have not aged well. After decades in storage, many of the videotapes in our collection now have sticky-shed syndrome, a condition in which the oxide that holds the visual content is literally flaking off the polyester tape base, and is gummy in texture. When a videotape has sticky-shed, not only will it not play correctly, the residue can also clog up the tape heads in the U-matic playback deck, then transfer the contaminant to other tapes played afterwards in the same deck. A U-matic videotape player in good working order is now an obsolete collector’s item, and our tapes are fragile, so we came up with a solution: throw those tapes in the oven!

oven2
After baking, the cookies (I mean U-matic videotapes) are ready for digitization!

At first that may sound reckless, but baking audio and videotapes at relatively low temperatures for an extended period of time is a well-tested method for minimizing the effects of sticky-shed syndrome. The Digital Production Center recently acquired a scientific oven, and after initial testing, we baked each Duke Living History U-matic videotape at 52 celsius (125 fahrenheit) for about 10 hours. Baking the videotapes temporarily removed the moisture that had accumulated in the binder, and made them playable for digitization. About 90% of our U-matic tapes played well after baking. Many of them were unplayable beforehand.

videoracks
The Digital Production Center’s video rack and routing system.

After giving the videotapes time to cool down, we digitize each tape, in real time, as an uncompressed  file (.mov) for long-term preservation. Afterwards, we make a smaller, compressed version (.mp4) of the same recording, which is our access copy. Our U-matic decks are housed in an efficiently-designed rack system, which also includes other obsolete videotape formats like VHS, Betacam and Hi8. Centralized audio and video routers allow us to quickly switch between formats while ensuring a clean, balanced and accurate conversion from analog to digital. Combining the art of analog tape baking with modern video digitization, the Digital Production Center is able to rescue the content from the videotapes, before the magnetic tape ages and degrades any further. While the U-matic tapes are nearing the end of their life-span, the digital surrogates will potentially last for centuries to come. We are able to benefit from Mr. Rutherfurd’s exciting experiment into our future, and carry it forward… into your future. May it illuminate well, educate wisely, and relate meaningfully, for future generations.

 

Post contributed by Alex Marsh

 

Society of North Carolina Archivists Annual Meeting Slides

On Tuesday April 8, I had the honor of presenting at the annual meeting of the Society of North Carolina Archivists with representatives from Wake Forest University and Davidson College. The focus of our panel was to present alternatives to CONTENTdm, a system for displaying digital collections widely used by libraries. At Duke, we have developed our own Tripod interface to digital collections. Wake Forest and Davidson use a variety of tools most notably DSpace and Islandora (via Lyrasis) respectively. It was great to present with and learn more about the Wake Forest and Davidson programs! I’ve embedded slides from all three speakers below.





A New Dimension for Duke’s Digital Collections

As our long-term readers of Bitstreams will attest, the Duke Digital Collections program has an established and well-earned reputation as a trailblazer when it comes to introducing new technologies, improved user interfaces, high definition imaging, and other features that deliver digital images with a beauty and verisimilitude true to the originals held by the David M. Rubenstein Rare Book & Manuscript Library.  Thus, we are particularly proud to launch today our newest feature, Smell-O-Bit, which adds a whole new dimension to the digital collections experience.

Smell-O-Bit is a cutting-edge technology that utilizes the diffusers built into most recent model computers to emit predefined scents associated with select digital objects within the Duke Digital Collections site.  While still in a test phase, the Digital Collections team has already tagged several images with scents that evoke the mood or content of key images.   To experience the smells, simply select Ctl-Alt-W-Up- while viewing these test images:

 

A bold scent for a bold product, Pabst-ett cheese!

Made by the Pabst brewing company while beer was off limits due to Prohibition, Pabst-ett cheese was soft, spreadable, and comfort-food delicious.  We’ve selected a bold, tangy scent to highlight these comforts.  The scent may make you happy enough to slap your own cheeks!

The smell of late a night chess match.

The smell of cigarette smoke, margaritas, and salt from around glass rims and chess players’ brows will make you feel as if you have front row seating at this chess match between composer John Cage and a worthy, but anonymous opponent.

A scent strong enough to eat!

You may feel yourself  overwhelmed with the wafting scent of char-broiled deliciousness, but don’t forget to take a deep inhale to detect the pickles, ketchup, and mustard which makes this a savory image all around.

Perhaps you smell garbage? If so, your Garbex isn’t working!  What about flies, cats, or dogs? Or, perhaps you just smell a rat. Alright, you caught us.

Happy April Fool’s Day from Duke Digital Collections!!

Post Contributed by Duke Digital Collections

 

Schema.org and Google for Local Discovery: Some Key Takeaways

Google CSE & schema.orgOver the past year and a half, among our many other projects, we have been experimenting with a creative new approach to powering searches within digital collections and finding aids using Google’s index of our structured data. My colleague Will Sexton and I have presented this idea in numerous venues, most recently and thoroughly for a recorded ASERL (Association of Southeastern Research Libraries) webinar on June 6, 2013.

We’re eager to share what we’ve learned to date and hope this new blog will make a good outlet. We’ve had some success, but have also encountered some considerable pitfalls along the way.

What We Set Out to Do

I won’t recap all the fine details of the project here, but in a nutshell, here are the problems we’ve been attempting to address:

  • Maintaining our own Solr index takes a ton of time to do right. We don’t have a ton of time.
  • Staff have noted poor relevance rank and poor support for search using non-Roman characters.
  • Our digital collections search box is actually used sparsely (in only 12% of visits).
  • External discovery (e.g., via Google) is of equal or greater importance vs. our local search for these “inside-out” resources.

Here’s our three-step strategy:

  1. Embed schema.org data in our HTML (using RDFa Lite)
  2. Get Google to index all of our embedded structured data
  3. Use Google’s index of our structured data to power our local search for finding aids & digital collections

Where We Are Today

We mapped several of our metadata fields to schema.org terms, then embedded that schema.org data in all 74,000 digital object pages and all 2,100 finding aids. We’re now using Google’s index of that data to power our default search for:

  1. All of our finding aids (a.k.a. collection guides).  [Example search for “photo”]
  2. One digital collection: Sidney Gamble Photographs. [Example search for “beijing”]

Though the strategy is the same, some of the implementation details are different between our finding aids and digital collections applications. Here are the main differences:

Site Service Google CSE API Max Results per Query
Finding Aids Google Custom Search (free) JS v1.0 100
Digital Collection Google Site Search
(premium version of Custom Search)
XML API 1,000

 

Finding Aids Search

Embedding the Data. We kept it super simple here. We labeled every finding aid page a ‘CollectionPage’ and tagged only a few properties: name, description, creator, and if present, a thumbnailUrl for a collection with digitized content.

Schema.org tags using RDFa Lite in finding aid HTML
Schema.org tags using RDFa Lite in finding aid HTML

Rendering Search Results Using Google’s Index. 

This worked great. We used a Google Custom Search Element (CSE) and created our own “rich snippets” using the CSE JavaScript API (v1.0) and the handy templating options Google provides. You can simply “View Source” to see the underlying code: it’s all there in the HTML. The HTML5 data- attributes set all the content and the display logic.

Google Javascript objects used in search result snippet presentation.
Google Javascript objects used in search result snippet presentation.

 

Digital Collections Search: Sidney D. Gamble Collection

Embedding the Data.

Our digital collections introduce more complexity in the structured data than we see in our finding aids. Naturally, we have a wide range of item types with diverse metadata. We want our markup to represent the relationship of an item to its source collection. The item, the webpage that it’s on, the collection it came from, and the media files associated with it all have properties that can be expressed using schema.org terms. So, we tried it all.[1]

Example Schema.org tags used in item pages
Example Schema.org tags used in item pages

Rendering Search Results Using Google’s Index. 

For the Gamble collection, we succeeded in making queries hit Google’s XML API while sustaining the look of our existing search results. Note that the facets in the left side aren’t powered via Google–we haven’t gotten far enough in our experiment to work with filtering the result set based on the structured data, but that’s possible to do.

Search result rendering using Google's XML API
Search result rendering using Google’s XML API

Outcomes 

 

The Good

We’ve been pleased with the ability to make our own rich snippets and highly customize the appearance of search results without having to do a ton of development. Getting our structured data back from Google’s index to work with is an awesome service and developing around the schema.org properties that we were already providing has been a nice way to kill two birds with one stone.

For performance, Google CSE is working well in both the finding aids and the Gamble digital collection search for these purposes:

  • getting the most relevant content presented early on in the search result
  • getting results quickly
  • handling non-Roman characters in search terms
  • retrieving a needle in a haystack — an item or handful of items that contain some unique text

The Gotchas

While Google CSE  shows relevant results quickly, we’re finding it’s not a good fit for exploratory searching when either of these aspects is important:

  • getting a stable and precise count of relevant results
  • browsing an exhaustive list of results that match a general query

Be careful: queries max out at 100 results with the JavaScript APIs or 1,000 results when using the XML API.  Those limits aren’t obvious in the documentation, yet they might be a deal-breaker for some potential uses.

For queries with several pages of hits, you may get an estimated result count that’s close, but unfortunately things occasionally and inexplicably go sour as you navigate from from one result page to the next.  E.g., the Gamble digital collection query ‘beijing‘ shows about 2,100 results (which is in the ballpark of what Solr returns), yet browse a few pages in and the result set will get truncated severely: you may only be able to actually browse about 200 of the results without issuing more specific query terms.

Other Considerations

Impact on External Discovery

Traffic to digital collections via external search engines has mostly climbed steadily every quarter for the past few years, from 26% of all visits in Jul-Sep 2011 up to 44% from Jan-Mar 2014 (to date) [2]. We entered schema.org tags in Oct 2012, however we don’t know whether adding that data has contributed at all to this trend. Does schema.org data impact relevance? It’s hard to tell.

Structured Data Syntax + Google APIs

Though RDFa Lite and microdata should be equally acceptable ways to add schema.org tags, Google’s APIs actually work better with microdata if there are nested item types.[3]  And regardless of microdata or RDFa, the Google CSE JavaScript API unfortunately can’t access more than one value for any given property, so that can be problematic [4].

Rich Snippets in Big Google

We’re seeing Google render rich snippets for our videos, because we’ve marked them as schema.org VideoObjects with properties like thumbnailUrl. That’s encouraging! Perhaps someday Google will render better snippets for things like photographs (of which we have a bunch), or maybe even more library domain-specific materials like digitized oral histories, manuscripts, and newspapers.  But at present, none of our other objects seem to trigger nice snippets like this.

A rich snippet triggered by using schema.org videoObject type & thumbnailUrl property.
A rich snippet triggered by using schema.org videoObject type & thumbnailUrl property.

Footnotes

[1] We represented item pages as schema.org “ItemPage” types using the “ispartOf” property to relate the item page to its corresponding “CollectionPage”. We made the ItemPage “about” a “CreativeWork”. Then we created mappings for many of our metadata fields to CreativeWork properties, e.g., creator, contentLocation, genre, dateCreated.

[2] Digital Collections External Search Traffic by Quarter

Quarter    Visits via Search   % Visits via Search

Jul – Sep 2011   26,621   25.97%
Oct – Dec 2011   32,191   29.59%
Jan – Mar 2012   41,048   32.16%
Apr – Jun 2012   33,872   34.49%
Jul – Sep 2012   28,250   32.40%
Oct – Dec 2012   38,472   36.52% <– entered schema.org tags Oct 19, 2012
Jan – Mar 2013   39,948   35.29%
Apr – Jun 2013   36,641   38.30%
Jul – Sep 2013   35,058   41.88%
Oct – Dec 2013   46,082   43.98%
Jan – Mar 2014   47,123   43.93%

[3] For example, if your RDFa indicates that “an ItemPage is about a CreativeWork whose creator is Sidney Gamble”– the creator of the creative work is not accessible to the API since the CreativeWork is not a top-level item.  To get around that, we had to duplicate all the CreativeWork properties in the HTML <head>, which is unnatural and a bit of a hack.

[4]  Google’s CSE JS APIs also don’t let us retrieve the data when there are multiple values specified for the same field. For a given CreativeWork, we might have six locations that are all important to represent: China; Beijing (China); Huabei xie he nu zi da xue (Beijing, China); 中国; 北京;  华北协和女子大学.  The JSON returned by the API only contains the first value: ‘China’. This, plus the result count limit, made the XML API our only viable choice for digital collections.

Digitization Details: Sidney D. Gamble’s Lantern Slides

I have worked in the Digital Production Center since March of 2005 and I’ve seen a lot of digital collections published in my time here.  I have seen so many images that sometimes it is difficult to say which collection is my favorite but the Sidney D. Gamble Photographs have always been near the top.

The Sidney D. Gamble Photographs are an amazing collection of black and white photographs of daily life in China taken between 1908 and 1932.  These documentary style images of urban and rural life, public events, architecture, religious statuary, and the countryside really resonate with me for their unopposed moment in time feel.  Recently the Digital Collections Implementation Team was tasked with digitizing a subset of lantern slides from this collection.  What is a lantern slide you might ask?

RL_10074_LS_0105_large
Herding Ducks

A lantern slide is a photographic transparency which is glass-mounted and often hand-colored for projection by a “magic lantern.”  The magic lantern was the earliest form of slide projector which, in its earliest incarnation, used candles to project painted slides onto a wall or cloth screen.   The projectionist was often hidden from the audience making it seem more magical.   By the time the 1840s rolled around photographic processes had been developed by William and Frederick Langenheim that enabled a glass plate negative to be printed onto another glass plate by a contact method creating a positive.  These positives were then painted in the same fashion that the earlier slides were painted (think Kodachrome).  The magic lantern predates the school slate and the chalkboard for use in a classroom.

After working with and enjoying the digitization of the nitrate negatives from the Sidney D. Gamble Photographs it has been icing on the cake to work with the lantern slides from the same collection so many years later.  While the original black and white images resonate with me the lantern slides have added a whole new dimension to the experience.  On one hand the black and white images lend a sense of history and times passed and on the other, the vivid colors of the lantern slides draw me into the scene as if it were the present.

RL_10074_LS_0297_large
Barbers on Bund

I am in awe of the amount of work and the variety of skill sets required to create a collection such as this.   Sidney D. Gamble, an amateur photographer, to trek across China over 4 trips spanning 24 years, photographing and processing nitrate negatives in the field without a traditional darkroom, all the while taking notes and labeling the negatives.  Then to come home and create the glass plate positives and hand color over 500 of them.  For being an “amateur photographer” Gamble’s images are striking.  The type of camera he used takes skill and knowledge to create a reasonably correct exposure.  Processing the film is technically challenging in a traditional darkroom and is made much more difficult in the field.  Taking enough notes while shooting, processing and traveling so they make sense as a collection is a feat in itself.  The transfer from negative film to positive glass plates on such a scale is a tedious and technical venture.  Then to hand paint all of the slides takes additional skill and tools.  All of this makes digitization of the material look like child’s play.

An inventory of the hand-colored slides was created before digitization began.  Any hand-colored slides with existing black and white negatives were identified so they can be displayed together online.  A color-balanced light box was used to illuminate the lantern slides and a Phase One P65 Reprographic camera was used in conjunction with a precision Kaiser copy stand to capture them.   All of the equipment used in the Digital Production Center is color-calibrated and profiled so consistent results can be achieved from capture to capture.  This removes the majority of the subjective decision making from the digitization process.  Sidney D. Gamble had many variables to contend with to produce the lantern slides much like the Digital Collections Implementation Team deals with many variables when publishing a digital collection.  From conservation of the physical material, digitization, metadata, interface design to the technology used to deliver the images online and the servers and network that connect everything to make it happen, there are plenty of variables.  They are just different variables.

Nowadays we photograph and share the minutia of our lives.  When Sidney Gamble took his photographs he had to be much more deliberate.   I appreciate his deliberateness as much as I appreciate all the people involved in publishing collections.  I look forward to publication of the Sidney D. Gamble lantern slides in the near future and hope you will enjoy this collection as much as I have over the years.

Post Contributed by Mike Adamo

A Day in the Life of Digital Collections

I joined the digital collections team in early December 2013, and from day 1 I have been immersed in the details of our long list of unique projects, all with their own set of schedules, stakeholders, and resource needs.  My task has also been to evaluate and improve our overall workflow, create outreach and promotional opportunities (like this blog!), and really anything else that comes up that is related to digital projects. What does that all mean in terms of day-to-day work? It means I attend A LOT of meetings.

Haitian Declaration of Independence
Just another day in the Digital Production Center imaging the Haitian Declaration of Independence!

Luckily most of my meetings are absolutely fascinating and revolve around very exciting projects and materials.  Here are some of my favorite meetings from the last few weeks.  Truth be told, I didn’t go to all of these in one day, but they are a pretty representative sample of the types of meetings I do attend everyday.

Haitian Declaration of Independence:  Perhaps you have heard that the Rubenstein library has a copy of this historic document?  The digital collections implementation team recently met with RL curator Will Hansen to discuss digitizing and providing access to the declaration, and of course he brought it with him.  Its not that large to be honest, but very impressive.  In DPPS we are using this project as catalyst to implement an image server and a new document viewing tool to provide better access to documents like the declaration.

 

“Girl Lost in Thought at Fast Food Counter” Image from the William Gedney Digital Collection

Workflows, Workflows, workflows:  Every week I attend operational meetings with both the Duke Digital Collections Implementation teams and the Digital Production Center to discuss work in progress, scheduling, new projects, and how to perfect our ever changing workflows.  I presented, along with my colleagues from Digital Projects and Production Services as part of our monthly ITS meeting, First Wednesday, on our overall process and some of the changes we have been making since I came on board.  Check out all of our slides! 

Gedney:  Duke Digital Collections patrons are no strangers to the William Gedney Photographs and Writings digital collection.  The physical collection is being re-processed and we will be digitizing more of it later in 2014.  This is a large project with a long timeline, but we are so excited to provide access to more materials in one of our most popular digital collections.

 

Early Greek MS:  the Rubenstein Library has a large collection of early Greek manuscripts.  Many items have already been digitized, and Rubenstein Technical Services is in the process of cataloging them.     Once cataloging is complete, we will be able to plan the publishing aspects of this project.  Both DPPS and our colleagues in the Collaboratory for Classics Computing are thrilled to provide access to digital versions of these items.

Stay tuned for continuing developments in these and all the other projects we have in progress!

GreekMS
A scanned image from one of the Greek Manuscripts in the Rubenstein collection.

 

Post authored by Molly Bragg

Spring Break Travel Tips from Digital Collections

Leave Winter Behind

Today marks the beginning of Spring Break 2014 for Duke students!  We recognize that Spring Break is normally a time of quiet reflection, but for those interested in getting away this week, we’d like to offer some travel tips courtesy of our historic advertising collections.  There’s still time to plan your trip!  Let’s get started.

Dude Ranch Vacations

Where to Go

Sure, the beach is always popular with spring breakers, but consider some alternatives.  Did you know that now is the time to plan Dude Ranch Vacations?

How to Get There

With so many transportation options available it’s hard to choose.  Take in the scenery at a slower pace aboard the Vista Dome cars on the California Zephyr train, “the most talked about train in the country,” or go by Greyhound Bus to “meet the real America.

If efficiency is more your thing, travel by air to get to your destination a little faster, because, as American Airlines reminds us, “air is everywhere.”  Still not convinced?  Take United Airline’s advice: “All the Important People Fly nowadays.

Compared to buses and trains, modern air travel offers such an abundance of options and amenities. For an authentic Spring Break experience, you could reserve a seat on Resort Airline’s “Flying Houseparty” to the Caribbean or maybe grab a beverage in Continental Airline’s Coach Pub in the Sky as featured in the commercial below.

If you’re looking for something a bit more refined,  be sure to book a flight on United where master chefs demonstrate their “cosmopolitan artistry in the finest meals aloft” and where your flight attendant is guaranteed to meet United’s strict qualifications for employment (gender, age, height, weight, and marital status).

What to Take

vacation hair Whether you travel by air, train, or bus, you’ll want to pack only the essentials for your Spring Break getaway.  Start with Dr. West’s Travel Kit, which includes toothpaste and a mini-toothbrush in a “handsome sanitary glass container,” all for just 50 cents.  Be sure to include a bottle of Kreml Shampoo as well so you don’t get caught with embarrassing vacation hair.

Just because you’re traveling doesn’t mean you need to leave your entertainment at home. “Lead the Vacation Fun Parade” by packing super-tiny, ultra-compact Zenith portable radios (only 5 1/2 pounds!).

Finally, if you’re overwhelmed by too many travel options and would rather stay home, avoid the crowds, and spend your money elsewhere this Spring Break, treat yourself to something special:  It’s Spring, Get a Pontiac.

Post contributed by Noah Huffman

Announcing the Duke Chapel Recordings Digital Collection and Video Player!

Duke Digital Collections is excited to announce our newest digital collection: Duke Chapel Recordings!

 dukechapel

This digital collection consists of a selection of audio and video recordings from the extensive collection of Duke University Chapel recordings housed in the Duke University Archives, part of the David M. Rubenstein Rare Book & Manuscript Library.   The digital collection features 168 audio and video recordings from the chapel including sermons from notable African American and female preachers.  This project has been a fruitful collaboration between Duke Chapel, the Divinity School, the Rubenstein Library and of course the digital projects team in Duke University Libraries.  To learn more, visit the Devil’s Tale blog (the blog of the Rubenstein Library).

But wait, there’s more!

sermon video
Brenda Kirton speaks in this still from one of the Duke Chapel Recordings digital collection.

Fifteen of the recordings were digitized from VHS tapes and are available as video playable from within the digital collection.  These are our first digitized videos delivered via our own infrastructure. Our previous efforts have all relied on external platforms like YouTube, iTunes, and the Internet Archive to serve up the videos. While these tools are familiar to users, feature-rich, and built on a strong technological backbone, we have been intending for quite awhile to develop support for delivering digital video in-house.

When you view a video from the Duke Chapel Recordings, you’ll see a “poster frame” image of the featured speaker. Click the play button to begin (of course!) and the video will play within the page. Watching the videos is a “pseudo-streaming” or “progressive download” experience akin to YouTube. That is, you can start watching almost immediately, and you can click ahead to arbitrary points in the middle of the video at any time.  And while you might occasionally have to wait for things to buffer, videos should play smoothly on desktop, tablet, and smartphone devices, and can be easily enlarged to full-screen. Finally, there’s a Download link right below the video if you’d like to take the files with you.

Behind the scenes, we are using the robust JW Player tool, for which the Pro version was recently made available by site-license to the Duke community by our friends in the Office of Information Technology. JW Player is media player software that uses a combination of HTML5 video and Javascript. It can play video from a streaming server, but as in our case, it can also pseudo-stream video over HTTP via a standard web server. Using HTML5 video, the browser requests and receives only the chunks of the video file that it needs as it plays. Almost all of the major modern browsers support HTML5 video delivering H.264/AAC MP4 content (our video encoding of choice), and a peek at our use statistics indicates that more than 80% of our users visit our site with these browsers.  For the rest, JW Player renders a nearly identical media player using Adobe Flash.

We’re looking forward to hearing from our users and learning from our peers who are working with digital media to keep refining our approach.  We hope to make many more videos from our collections available in the near future.

Post authored by Sean Aery and Molly Bragg.

Digitization Details: Re-Formatting Audio Cassettes

Cassette
A real live audio cassette!

The 310 oral histories that comprise the newly published additions to the Behind the Veil digital collection were originally recorded in the 1990’s to the now (nearly) obsolete compact cassette format—what were commonly called “tapes”.  The beauty of the compact cassette format was that it was small and portable (especially compared to the earlier reel-to-reel tape format), relatively durable due to its hard plastic outer shell, and most of all—could easily be recorded to at home by non-professional users.  This made it perfect for oral historians who needed to be able to record interviews in the field at low cost with minimal hassle.  

Unfortunately, the compact cassette format hasn’t aged particularly well.  Due to cheap materials, poor storage conditions, and normal mechanical wear and tear, many of these tapes are already borderline unplayable a short 40 years after their first introduction.  This introduces a number of challenges to our process of converting the audio information on the tapes into a digital file format that can easily be accessed online by patrons.  I won’t exhaustively detail our digitization process here, but only touch on a few issues and how we dealt with them.

Inspecting a tape
Our fearless audio digitization expert carefully inspects a tapes.

Physical degradation and damage to tapes: We visually inspected each tape prior to digitization.  Any that were visibly broken or had twisted or jammed tape were rehoused in new outer shells.  At least with this collection, rehousing allowed us to successfully play back all of the tapes.

Poor quality of original recordings: We also did a brief audio inspection of each tape before digitization.  This allowed us to identify issues with audio quality.  We found that the interviews were done in a wide variety of locations, often with background traffic, television, appliance and conversation noise bleeding into the recording.  There was no easy fix for this, as these issues are inherent in the recording.  Our solution was to provide the best possible playback on a high-quality cassette deck, a direct and balanced signal path, and high quality analog-to-digital conversion at the preservation standard of 24 bits, 96.1 kHz.  This ensured that the digital copy faithfully reproduced the audio material on the cassette, warts and all.

Other errors in original recordings: There were some issues in the original recordings that we opted to fix via digital editing or processing in our files for patron use (while retaining the unaltered preservation files).

  • In cases where there was a significant gap of silence in the middle of a tape, we edited out the silence for continuity’s sake.
  • In cases where there were loud and abrasive clicks, pops, or microphone noise at the beginning or end of a tape side, we edited out these noises.
  • Several tapes were apparently recorded at the wrong speed, resulting in a “chipmunk voice” effect.  I used a Speed/Pitch function in our audio capture software to electronically slow these files down so that they play back intelligibly and as intended.
deck
Audio digitization deck

Another challenge, common to all time-based analog media, is the cassette tape’s “real-time” nature.  Unlike a digital file that can be copied nearly instantaneously, a 90-minute cassette tape actually takes 90 minutes to make a digital copy.  Currently we run two cassette decks simultaneously, allowing us to double our throughput.

As you can see, audio cassette digitization is more than just a matter of pressing “play”!

–post written by Zeke Graves

Still want to learn more about the Behind the Veil collection of oral histories?  Check out coverage of the collection over at Rubenstein Library blog, The Devil’s Tale.

 

Notes from the Duke University Libraries Digital Projects Team