Friday, August 3, 2012

ICT · The Image Citation Tool

The Homer Multitext has developed an Image Citation Tool for use with digital images served by the CITE Image Service.

Humanist scholarship is the act of forging new connections between ideas, and placing those connections before the eyes of readers. Those readers must be free and empowered to judge the value of the new connections.

The heart of humanist scholarship, then in quotation. Robert Sokolowski calls quotation a ‘curious conjunction of begin able to name and to contain’;* V.A. Howard is more succinct: quotation is ‘replication-plus-reference’.** We would re-phrase this as “reproduction plus citation”.

Reproduction in a quotation allows us to talk about a particular artifact of human thought without the burden of reproducing its entire context. As a practical matter, it is easier to say “Μῆνιν ἄειδε θεὰ Πηληϊάδεω Ἀχιλῆος” than to reproduce the whole of the Iliad.

Citation in a quotation provides a link from the reproduced selection back to context of that selection. “Iliad 1.1” names our quotation, as Howard says, but also invites the reader to explore Iliad 1.2, all of Book 1 of the Iliad, or the whole poem.

This is easy stuff. We were all taught to do it early in our educations, and we take it for granted.
It is easy, that is, with texts. Images are a different matter. How do you “quote” from an image? Most scholars use images from time to time in their work; few of those uses meet the rigorous standards of “quotation” that we take for granted with texts. The general practice is to open a digital image in an image-editor, cut out the area of the image under discussion, and paste that image into a document or web-page. If the image is cited, the citation is often to a page in a book that has published a version of the image, a museum’s accession number identifying an original work of art, or a URL to a web-page on which a digital version of the image appears. The citation does not provide a path from the selection to its context.

Nor is this kind of “image quotation” actionable in the way that a textual quotation (reproduction+citation) is. Given “Iliad 1.1”, it is simple to answer the question “What comes next?”. It is simple to know that “Iliad 1.1–1.10” includes Iliad 1.5. Given a cut-copied-pasted snippet of a digital image, and perhaps a citation to a web-page, it is not possible to answer with any degree of precision “Where is this snippet in its larger context? What parts of the image are adjacent to this snippet?” Given two snippets, it would require considerable computation to determine whether Snippet A contains Snippet B.

Since the Homer Multitext is committed to image-based scholarly editing, and subsequent discussion and argument based closely on digital imagery of manuscripts and papyri, we have worked to developed a means of quoting images as rigorously, and usefully, as we can quote texts.

The CITE Image Service allows us to identify images with canonical citations in URN-notation. These URNs take the form: urn:cite:hmt:chsimg.VA094VN-0597. This points to a notional image, which might be delivered at any scale, or by services hosted on various machines with various addresses.
A CITE Image URN can take a suffix that identifies a rectangular region-of-interest: urn:cite:hmt:chsimg.VA094VN-0597:0.3833,0.2441,0.0783,0.0463. This URN+ROI can resolve to a “quotation”, that is the region-of-interest on its own, or to a view of the larger image with the region-of-interest highlighted. These image-ROIs canonically cited with URN notation are concise, precise, and machine-actionable mechanisms for image quotation in the best tradition of humanist scholarship.

To help ourselves, our collaborators, and anyone else interested in working with the openly licensed images in our Homer Multitext Image Collection, we have developed a web-based tool for defining regions-of-interest on our digital images and capturing canonical citations for them. This is the Image Citation Tool.

A lengthy introduction to the tool and its use are included in our Homer Multitext documentation pages.   Downloadable source-code for the tool—a relatively simple web-application in HTML, CSS, and Javascript—is available from the HMT’s code repository.


* Sokolowski, Robert. “Quotation.” The Review of Metaphysics 37.4 (1984) : 699-723. Print. 24 May 2011.
** Howard, V.A., “On Musical Quotation”, Monist 58 (1974) 310.