Lisa Tweten has recently graduated from the Classical, Near Eastern and Religious Studies department at the University of British Columbia with a Masters degree in the Ancient Cultures, Religion, and Ethnicity program. As one of the project managers of From Stone to Screen, Lisa photographed and edited the digital collection of epigraphic squeezes, and has continued to work on the content management and database for the project with the Digital Initiatives branch of the UBC library.
Gwynaeth McIntyre (Lecturer, University of Otago) was the faculty advisor on the student-launched digitization project entitled
Chelsea Gardner is a PhD candidate in Classical Archaeology at the University of British Columbia. As one of the project managers of From Stone to Screen, Chelsea uploaded and edited the metadata for the online collection of epigraphic squeezes, and has headed several international collaborations for the project. Her dissertation work focuses on cultural identity in the Mani peninsula of southern Greece.
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This article outlines an innovative photographic technique used to digitize the Malcolm Francis McGregor Epigraphic Squeeze collection held by the Department of Classical, Near Eastern and Religious Studies at the University of British Columbia (UBC) in collaboration with a branch of the UBC library system called Digital Initiatives. The squeezes are photographed using a TTI Repro-Graphic Workstation 4060, Sinar 86H cameraback and digital CMV lenses using CaptureShop image processing software. The images undergo further processing using Photoshop CS6 and the HDR merge and Photomerge tools. The result creates a stunningly clear image which fully captures the details of the squeeze and specifically its three-dimensional quality.
outlines a photographic technique used to digitize the Malcolm Francis McGregor Epigraphic Squeeze collection held by the Department of Classical, Near Eastern and Religious Studies at the University of British Columbia (UBC)
As the field of Digital Humanities grows and the interest in
digital resources for teaching and research increases,
scholars are finding new and innovative ways to make
traditionally inaccessible or restricted material available
to a wider audience. Due to the fragile nature of some
teaching and research collections, especially those
comprising material from the Greek and Roman worlds,
curators are constantly presented with the challenge of
finding photographic techniques which safely and effectively
replicate the objects in digital format. Many such projects
include the University of Florida’s Digital Epigraphy and
Archaeology project, the Smithsonian’s digitization of the
Freer Gallery of Art and the Arthur M. Sackler Gallery
Archives and Cornell University Library’s Photographs of
Stones – Mysteries at Eleusis.th century to
the 2nd century BCE.
While a squeeze in general refers to a molding, cast,
impression, or copy of an object or design made by pressing
a pliable substance around or over it, an epigraphic squeeze
in particular is the impression of an inscription on stone.
This specific variety of squeeze utilizes filter paper, a
porous paper for filtering liquids most often employed in
the field of chemistry. The process of creating a squeeze is
quite simple: first, the filter paper is dampened and placed
atop the inscription. Next, a horsehair brush is used to hit
the paper so that the paper is pressed into the grooves of
the stone. Finally, once the paper has dried, it is
carefully peeled off and a mirror copy of the inscription is
revealed.
The final product is known as an epigraphic squeeze and is
an invaluable tool for research in the field of Greek and
Latin epigraphy – when encountered in the field,
inscriptions are most commonly located on immovable stones,
either due to their substantial size or their secondary use
as
Although the advantages of using squeezes for research far outweigh the disadvantages, there are some issues associated with their use. First, squeezes are difficult to store and to maintain long-term. While the modified filter paper does provide a mirror copy of the inscription, the paper itself is thin, fragile and prone to disintegration, tearing, water damage, and mold. Second, the squeezes themselves must be stored flat and separated into small piles of only a few squeezes so that the weight of the topmost squeezes does not flatten the letters on those below. For this reason they are commonly stored in thin drawers in customized cabinets made expressly for this purpose. Third, because the direct impression of the inscription is found on the underside of the squeeze, epigraphic squeezes are often read backwards since the letter forms are more legible on this side. The reader must then read the squeeze from right to left, using a magnifying glass to see all of the details necessary for a thorough analysis of the inscription. Finally, the curators of epigraphic collections of many museums – including one of the only epigraphic museums in the world, the Athens Epigraphical Museum – have issued a ban on the creation of additional squeezes for fear of further damaging the stone inscription The implication of this ban is that already-established squeeze collections are likely to be the only such collections that will ever exist. This fact renders the existing collections all the more precious, and the various digitization projects even more significant. The fragility of squeeze collections highlights the importance of creating digital records of these important historical documents which preserve the detail and three-dimensional nature of the squeeze and the information contained within it.
This article outlines an innovative photographic technique
that was employed by the CNERS department at UBC, in
collaboration with a branch of the UBC library system called
Digital Initiatives. This technique effectively reproduces
the three-dimensional quality of the squeeze. Once the
images have been uploaded to the digital collections website,
The McGregor squeeze collection was donated by Dr. Malcolm
McGregor, renowned scholar of Athenian history and Greek
epigraphy and a former professor in the Department of
Classics (before it was merged with Near Eastern and
Religious Studies) at UBC. His collection largely comprises
inscriptions from Attica from the 5th century BCE, some inscriptions from Nemea
(approximately 100 km south-west of Athens) from the same
period, and several decrees dating to the 2nd century BCE. This collection
contains 1051 squeezes and, although this number includes
several duplicate copies of select inscriptions, access to
this large amount of material allows for the possibility of
studying inscriptions from these geographic areas and
periods in one place. The most notable squeezes in the
collection are the squeezes of the Athenian Tribute Lists
(ATLs), which were the main focus of McGregor’s research for
many years and the subject of his formative work: together
with H.T. Wade-Gery and B.D. Merritt, McGregor authored the
definitive volumes on a reconstruction of these lists which
include both texts and translations of the documents
(Meritt, Wade-Gery, McGregor 1939-1953). The McGregor
squeeze collection at UBC is a result of the research and
study carried out for these volumes. The original
inscriptions are held in the Athens Epigraphical Museum and
are difficult for scholars to study firsthand, as their
monumental height (3.5 m at their tallest) reduces
visibility.
The Athenian Tribute Lists themselves are enormous
dedications to Athena which once stood on the Acropolis of
Athens. These inscribed records list the annual
first-fruits
) dedicated to
the goddess Athena by members of the Delian League, a group
of allied cities who pooled their resources against the
threat of a Persian invasion of Greece. The
th century BCE Aegean.
The largest stone, the Lapis Primus (literally, first
stone
) records the
The greatest challenge in creating superior digital images
of epigraphic squeezes is the three-dimensional nature of
the squeeze as an object. The letter forms of most squeezes
are only slightly indented, due to the shallow carving on
the stones themselves and, as mentioned above, scholars
working with the squeezes themselves generally find them
easier to read by reading the underside so that the letters
are raised – the implication of this methodology is that the
words are read backwards, from right to left. A simple
photograph of the squeeze produces a flat and often
illegible image that does not allow for a detailed study of
the letter forms, eliminating potential reconstructions of
fragmentary inscriptions. Alternatively, flatbed scanning
runs the risk of flattening the raised letters, forever
altering the quality of the original squeeze. One research
group attempting to digitize squeezes has pioneered the use
of surface reconstruction to create a three-dimensional
image from a two-dimensional photograph of the epigraphic
squeeze
The original goal for the digitization of the McGregor
collection was to find a non-destructive process that would
generate crisp, detailed images that retained the
three-dimensional nature of the squeeze. In the summer of
2013, two assistants from the UBC Library’s Digitization
Centre (generally referred to as Digital Initiatives, or
DI),
The TTI workstation features a 4x6 foot vacuum table with mounted lights and a suspended camera. The underside of the squeeze is then placed facing up as this is the part of the squeeze which has come into direct contact with the stone of the inscription and thus it retains the direct imprint of the inscription. This is the most important image to capture faithfully in the digitization process. The squeeze is photographed using a Sinar 86H cameraback and digital CMV lenses which uses CaptureShop image processing software. The camera shoots four frames per image in an X-pattern, from top left to bottom right, then bottom left to top right, shifting by a single pixel per frame.
CaptureShop then merges the resulting four frames into a
single image. The single pixel shift creates a composite
image that is an extremely precise representation of the
original item being photographed. While this is the standard
procedure used by Digital Initiatives, capturing the unique
three-dimensional quality of the squeezes requires clarity
and definition in both the highlights and lowlights.
Expanding on a technique developed for creating Polynomial
Texture Maps and for Reflectance Transformation Imaging
The RAW image files are imported into Photoshop CS6 where the automated HDR merge function is used to create a single image with all of the dynamic range of the three different exposures. RAW files are used in this case because they retain the maximum amount of information from the captured images; compressing the image to TIF or JPG format results in both a loss of detail and images incompatible with the HDR merge tool. In the case of the larger squeezes, Photoshop’s Photomerge tool was used to fully capture the original squeeze. Even though the vacuum table of the TTI measures 4x6 feet, the total area captured by the camera is much smaller even when the camera is raised to its highest level on the support arm. In these situations, a series of pictures are taken, ensuring that there is at least a 30% overlap of pixels within each image. Photoshop can then use this overlap to seamlessly stitch the images together using the Photomerge tool. It is more time-effective to take four photos with considerable overlap than to attempt this maneuver with only three photos – this often leads to insufficient pixel correlation to create a collage and one must then start over. The photographic and post-processing techniques described above create an image with the texture of the paper beautifully enhanced.
Next, the image of the squeeze undergoes further editing in
Photoshop: flipping it horizontally allows the letters to be
read left to right and the image is straightened so the
text, not the edge of the filter paper, is horizontal to the
reader. While epigraphists are accustomed to reading
squeezes backward, or right to left, the flipped images
available on our website makes the resource more accessible
to students of ancient Greek. Other edits, including the
insertion of a neutral grey background and drop shadow, are
purely aesthetic, but are performed to match the images in
other digital collections in the University of British
Columbia’s library. The images are then uploaded to the
library’s digital collections website with basic metadata
including the title of the inscription, references, date of
the inscription, and number of squeezes and fragments
relating to this inscription in the collection.
The squeezes have been digitized, and we are currently expanding the metadata to include transliterations, translations, relevant bibliography, and other additional notes. Initial research by student volunteers has been focused on obtaining information about the physical stones containing the inscriptions – their dimensions, findspots and current locations. In July 2015, Chelsea Gardner obtained a permit from the Athens Epigraphical Museum to photograph some of the original inscriptions that we hold in our collection. The purpose of this collaboration was to better illustrate the squeezes at the core of the collection, including the Athenian Tribute Lists, and select inscriptions we use most frequently for undergraduate instruction. The stones of the ATL’s Lapis Primus have been reconstructed into the 3.5 meter-high replica of the original stele. While this allows the museum to showcase the inscriptions' monumental scale, this type of display makes photography of the stones decidedly difficult. Despite this, we were able to acquire the necessary images of the original stone inscriptions which will be added to our website for additional context for the squeezes. The addition of the photographs from the Epigraphical Museum will facilitate the use of the database as a comprehensive research and teaching tool for epigraphers, scholars, and students alike, since photos of many of these stones are not readily available elsewhere. By displaying the photograph and squeeze side-by-side on the website, interested parties (students, scholars, and the general public) can compare the quality of the words on the stone versus the squeeze for themselves and explore all resources available.
The digital collections interface allows users the means to view and manipulate the images without requiring additional software, offering a range of file sizes to download and an impressive zoom feature for detailed study of letterforms or ambiguities.
The test collection proved that the equipment in Digital
Initiatives would provide both the image-quality and
interface required for detailed study of the squeezes in the
McGregor collection. This digitization project was fortunate
enough to receive a grant from the University of British
Columbia for the express purpose of making archived material
digitally available through the university’s library system,
or in their own words to ensure the
authentic, long-term preservation of these digital
holdings for the future.
Although the TTI Repro-Graphic 4060 assemblage used in Digital Initiatives is prohibitively expensive, we strongly believe that the quality of our images and a similar workflow could be achieved at a lower cost to anyone interested in replicating our imaging process. The camera model and light array are available at different price points and in different sizes. The vacuum table is not essential and can be replaced with any flat surface. The most important aspects for reproducing our photographic technique are a camera stand to mount the camera over the squeeze; remote shutter capabilities to ensure that there is no shadow cast on the squeeze; and a bright, neutral light array installed on one side of the camera, placed at a 45 degree angle. While CaptureShop software automates the process of taking three different exposures of the squeeze, the same process could easily be done manually. In fact, DI upgraded from CaptureShop to CaptureFlow in September of 2014, and different program features – including the loss of the automatic bracketing feature used to photograph the majority of the squeezes – forced us to find an alternative method. We completed the squeeze photography by taking a single shot with the Sinar 86H camera and created bracketed images with Photoshop by creating two duplicate files and changing the exposure settings. From there, the process is identical to what was described above.
Photoshop C2 or newer is essential to replicate the overall quality of the images: this was the first version of Photoshop with the HDR-Merge tool. HDR merge will combine the RAW camera files of three different exposures into a single image, while still retaining the highlights and shadows from the over- and under-exposed images. For larger squeezes, the same technique as outlined above can be applied by taking multiple photos and then stitching them together using Photomerge. The process of digitally stitching images together with Photoshop is entirely automated and can be easily mastered by anyone with basic technological proficiency. Using this fundamental methodology, similar projects can replicate our process without the full technological arsenal that this project employs. DI is equipped with Photoshop CS5 and CS6, which have improved upon the early HDR-merge tool so we cannot attest to the usability or quality of merged images with earlier versions of Photoshop.
Scholars in the field of Greek epigraphy have long been able
to make squeezes of inscriptions but sharing them with the
broader academic community has been a continuous challenge.
The earliest publications of inscriptions – for example the
Supplementum Epigraphicum Graecum (SEG) and the
Inscriptiones Graecae (IG) - focused on providing
transcriptions of the text due to financial and practical
constraints of including photographs when the field of
photography was in its infancy. Thus, scholars had access to
the text of the inscriptions but vital contextual and visual
information was notably absent. A visual representation of
object itself is necessary for a balanced appreciation of
the inscription both as a text and as an archaeological
artifact
The imaging process presented in this article is simply the latest in a long line of predecessors; our project follows in the two-decade-old digital tradition, yet fully exploits the technological advancements and digitizing techniques used by recent projects in epigraphy, paleography, papyrology, and artifact digitization. This work undertaken by
the key to improving digital publication further appears to lie in the way in which scholars work together; the more interdisciplinarity can be encouraged, the better digital publications will become…Rather than holding back from working collaboratively, we should embrace the opportunities that technological advances present, and seek new ways to further our knowledge.
This project could not be undertaken without the financial support of the Teaching and Learning Enhancement Fund and the Department of Classical, Near Eastern and Religious Studies at the University of British Columbia. The authors would also like to thank Larissa Ringham, Lesley Field, Chris Pugh, and other DI staff for their assistance in the digitizaiton process, their expertise, and their innovative problem solving for developing the digitization process. We have had tremendous support from our department faculty, notably Lisa Cooper, Kevin Fisher, Melissa Funke, Charmaine Gorrie, Nigel Kennel, Toph Marshall, Matthew McCarty, Siobhan McElduff, Dietmar Neufeld, Shelley Reid, and Lynn Welton.
And finally, our work on the McGregor squeeze collection owes its gratitude to: David Assaf, Haley Bertram, Richard Cameron, Maude Côté-Landry, Katie Frankson, Stuart Hill, Emma Hilliard, Pinar Lombaard, Chloe Martin-Cabanne, Andrei Mihailiuk, Heather Odell, Kat Solberg, and Patricia Taylor.