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Workshop on Electronic Texts
Session V.

Approaches to Preparing Electronic Texts

HOCKEY

Susan HOCKEY, director, Center for Electronic Texts in the Humanities (CETH), Rutgers and Princeton Universities, announced that one talk (WEIBEL's) was moved into this session from the morning and that David Packard was unable to attend. The session would attempt to focus more on what one can do with a text in ASCII and the representation of electronic text rather than just an image, what one can do with a computer that cannot be done with a book or an image. It would be argued that one can do much more than just read a text, and from that starting point one can use markup and methods of preparing the text to take full advantage of the capability of the computer. That would lead to a discussion of what the European Community calls reusability, what may better be termed durability, that is, how to prepare or make a text that will last a long time and that can be used for as many applications as possible, which would lead to issues of improving intellectual access.

HOCKEY urged the need to look at ways of using markup to facilitate retrieval, not just for referencing or to help locate an item that is retrieved, but also to put markup tags in a text to help retrieve the thing sought either with linguistic tagging or interpretation. HOCKEY also argued that little advancement had occurred in the software tools currently available for retrieving and searching text. She pressed the desideratum of going beyond Boolean searches and performing more sophisticated searching, which the insertion of more markup in the text would facilitate. Thinking about electronic texts as opposed to images means considering material that will never appear in print form, or print will not be its primary form, that is, material which only appears in electronic form. HOCKEY alluded to the history and the need for markup and tagging and electronic text, which was developed through the use of computers in the humanities; as MICHELSON had observed, Father Busa had started in 1949 to prepare the first-ever text on the computer.

HOCKEY remarked several large projects, particularly in Europe, for the compilation of dictionaries, language studies, and language analysis, in which people have built up archives of text and have begun to recognize the need for an encoding format that will be reusable and multifunctional, that can be used not just to print the text, which may be assumed to be a byproduct of what one wants to do, but to structure it inside the computer so that it can be searched, built into a Hypertext system, etc.


WEIBEL

Stuart WEIBEL, senior research scientist, Online Computer Library Center, Inc. (OCLC), described OCLC's approach to preparing electronic text. He argued that the electronic world into which we are moving must accommodate not only the future but the past as well, and to some degree even the present. Thus, starting out at one end with retroconversion and keying of texts, one would like to move toward much more automated ways of developing data.

For example, Project ADAPT had to do with automatically converting document images into a structured document database with OCR text as indexing and also a little bit of automatic formatting and tagging of that text. The CORE project hosted by Cornell University, Bellcore, OCLC, the American Chemical Society, and Chemical Abstracts, constitutes WEIBEL's principal concern at the moment. This project is an example of converting text for which one already has a machine-readable version into a format more suitable for electronic delivery and database searching. (Since Michael LESK had previously described CORE, WEIBEL would say little concerning it.) Borrowing a chemical phrase, de novo synthesis, WEIBEL cited the Online Journal of Current Clinical Trials as an example of de novo electronic publishing, that is, a form in which the primary form of the information is electronic.

Project ADAPT, then, which OCLC completed a couple of years ago and in fact is about to resume, is a model in which one takes page images either in paper or microfilm and converts them automatically to a searchable electronic database, either on-line or local. The operating assumption is that accepting some blemishes in the data, especially for retroconversion of materials, will make it possible to accomplish more. Not enough money is available to support perfect conversion.

WEIBEL related several steps taken to perform image preprocessing (processing on the image before performing optical character recognition), as well as image postprocessing. He denied the existence of intelligent character recognition and asserted that what is wanted is page recognition, which is a long way off. OCLC has experimented with merging of multiple optical character recognition systems that will reduce errors from an unacceptable rate of 5 characters out of every l,000 to an unacceptable rate of 2 characters out of every l,000, but it is not good enough. It will never be perfect.

Concerning the CORE Project, WEIBEL observed that Bellcore is taking the topography files, extracting the page images, and converting those topography files to SGML markup. LESK hands that data off to OCLC, which builds that data into a Newton database, the same system that underlies the on-line system in virtually all of the reference products at OCLC. The long-term goal is to make the systems interoperable so that not just Bellcore's system and OCLC's system can access this data, but other systems can as well, and the key to that is the Z39.50 common command language and the full-text extension. Z39.50 is fine for MARC records, but is not enough to do it for full text (that is, make full texts interoperable).

WEIBEL next outlined the critical role of SGML for a variety of purposes, for example, as noted by HOCKEY, in the world of extremely large databases, using highly structured data to perform field searches. WEIBEL argued that by building the structure of the data in (i.e., the structure of the data originally on a printed page), it becomes easy to look at a journal article even if one cannot read the characters and know where the title or author is, or what the sections of that document would be. OCLC wants to make that structure explicit in the database, because it will be important for retrieval purposes.

The second big advantage of SGML is that it gives one the ability to build structure into the database that can be used for display purposes without contaminating the data with instructions about how to format things. The distinction lies between procedural markup, which tells one where to put dots on the page, and descriptive markup, which describes the elements of a document.

WEIBEL believes that there should be no procedural markup in the data at all, that the data should be completely unsullied by information about italics or boldness. That should be left up to the display device, whether that display device is a page printer or a screen display device. By keeping one's database free of that kind of contamination, one can make decisions down the road, for example, reorganize the data in ways that are not cramped by built-in notions of what should be italic and what should be bold. WEIBEL strongly advocated descriptive markup. As an example, he illustrated the index structure in the CORE data. With subsequent illustrated examples of markup, WEIBEL acknowledged the common complaint that SGML is hard to read in its native form, although markup decreases considerably once one gets into the body. Without the markup, however, one would not have the structure in the data. One can pass markup through a LaTeX processor and convert it relatively easily to a printed version of the document.

WEIBEL next illustrated an extremely cluttered screen dump of OCLC's system, in order to show as much as possible the inherent capability on the screen. (He noted parenthetically that he had become a supporter of X-Windows as a result of the progress of the CORE Project.) WEIBEL also illustrated the two major parts of the interface: l) a control box that allows one to generate lists of items, which resembles a small table of contents based on key words one wishes to search, and 2) a document viewer, which is a separate process in and of itself. He demonstrated how to follow links through the electronic database simply by selecting the appropriate button and bringing them up. He also noted problems that remain to be accommodated in the interface (e.g., as pointed out by LESK, what happens when users do not click on the icon for the figure).

Given the constraints of time, WEIBEL omitted a large number of ancillary items in order to say a few words concerning storage requirements and what will be required to put a lot of things on line. Since it is extremely expensive to reconvert all of this data, especially if it is just in paper form (and even if it is in electronic form in typesetting tapes), he advocated building journals electronically from the start. In that case, if one only has text graphics and indexing (which is all that one needs with de novo electronic publishing, because there is no need to go back and look at bit-maps of pages), one can get 10,000 journals of full text, or almost 6 million pages per year. These pages can be put in approximately 135 gigabytes of storage, which is not all that much, WEIBEL said. For twenty years, something less than three terabytes would be required. WEIBEL calculated the costs of storing this information as follows: If a gigabyte costs approximately $1,000, then a terabyte costs approximately $1 million to buy in terms of hardware. One also needs a building to put it in and a staff like OCLC to handle that information. So, to support a terabyte, multiply by five, which gives $5 million per year for a supported terabyte of data.

DISCUSSION

During the question-and-answer period that followed WEIBEL's presentation, these clarifications emerged. The tapes saved by the American Chemical Society are the typography files that originally supported the publication of the journal. Although they are not tagged in SGML, they are tagged in very fine detail. Every single sentence is marked, all the registry numbers, all the publications issues, dates, and volumes. No cost figures on tagging material on a per-megabyte basis were available. Because ACS's typesetting system runs from tagged text, there is no extra cost per article. It was unknown what it costs ACS to keyboard the tagged text rather than just keyboard the text in the cheapest process. In other words, since one intends to publish things and will need to build tagged text into a typography system in any case, if one does that in such a way that it can drive not only typography but an electronic system (which is what ACS intends to do--move to SGML publishing), the marginal cost is zero. The marginal cost represents the cost of building tagged text into the database, which is small.


SPERBERG-McQUEEN

Prior to speaking about SGML and markup, Michael SPERBERG-McQUEEN, editor, Text Encoding Initiative (TEI), University of Illinois-Chicago, first drew a distinction between texts and computers: Texts are abstract cultural and linguistic objects while computers are complicated physical devices, he said. Abstract objects cannot be placed inside physical devices; with computers one can only represent text and act upon those representations.

The recognition that all representation is encoding, SPERBERG-McQUEEN argued, leads to the recognition of two things: 1) The topic description for this session is slightly misleading, because there can be no discussion of pros and cons of text-coding unless what one means is pros and cons of working with text with computers. 2) No text can be represented in a computer without some sort of encoding; images are one way of encoding text, ASCII is another, SGML yet another. There is no encoding without some information loss, that is, there is no perfect reproduction of a text that allows one to do away with the original. Thus, the question becomes, What is the most useful representation of text for a serious work? This depends on what kind of serious work one is talking about.

The projects demonstrated the previous day all involved highly complex information and fairly complex manipulation of the textual material. In order to use that complicated information, one has to calculate it slowly or manually and store the result. It needs to be stored, therefore, as part of one's representation of the text. Thus, one needs to store the structure in the text. To deal with complicated representations of text, one needs somehow to control the complexity of the representation of a text; that means one needs a way of finding out whether a document and an electronic representation of a document is legal or not; and that means one needs a grammar of documents.

SPERBERG-McQUEEN discussed the variety of forms of formal grammars, implicit and explicit, as applied to text, and their capabilities. He argued that these grammars correspond to different models of text that different developers have. For example, one implicit model of the text is that there is no internal structure, but just one thing after another, a few characters and then perhaps a start-title command, and then a few more characters and an end-title command. SPERBERG-McQUEEN also distinguished several kinds of text that have a sort of hierarchical structure that is not very well defined, which, typically, corresponds to grammars that are not very well defined, as well as hierarchies that are very well defined (e.g., the Thesaurus Linguae Graecae) and extremely complicated things such as SGML, which handle strictly hierarchical data very nicely.

SPERBERG-McQUEEN conceded that one other model not illustrated on his two displays was the model of text as a bit-mapped image, an image of a page, and confessed to having been converted to a limited extent by the Workshop to the view that electronic images constitute a promising, probably superior alternative to microfilming. But he was not convinced that electronic images represent a serious attempt to represent text in electronic form. Many of their problems stem from the fact that they are not direct attempts to represent the text but attempts to represent the page, thus making them representations of representations.

In this situation of increasingly complicated textual information and the need to control that complexity in a useful way (which begs the question of the need for good textual grammars), one has the introduction of SGML. With SGML, one can develop specific document-type declarations for specific text types or, as with the TEI, attempts to generate general document-type declarations that can handle all sorts of text. The TEI is an attempt to develop formats for text representation that will ensure the kind of reusability and longevity of data discussed earlier. It offers a way to stay alive in the state of permanent technological revolution.

It has been a continuing challenge in the TEI to create document grammars that do some work in controlling the complexity of the textual object but also allowing one to represent the real text that one will find. Fundamental to the notion of the TEI is that TEI conformance allows one the ability to extend or modify the TEI tag set so that it fits the text that one is attempting to represent.

SPERBERG-McQUEEN next outlined the administrative background of the TEI. The TEI is an international project to develop and disseminate guidelines for the encoding and interchange of machine-readable text. It is sponsored by the Association for Computers in the Humanities, the Association for Computational Linguistics, and the Association for Literary and Linguistic Computing. Representatives of numerous other professional societies sit on its advisory board. The TEI has a number of affiliated projects that have provided assistance by testing drafts of the guidelines.

Among the design goals for the TEI tag set, the scheme first of all must meet the needs of research, because the TEI came out of the research community, which did not feel adequately served by existing tag sets. The tag set must be extensive as well as compatible with existing and emerging standards. In 1990, version 1.0 of the Guidelines was released (SPERBERG-McQUEEN illustrated their contents).

SPERBERG-McQUEEN noted that one problem besetting electronic text has been the lack of adequate internal or external documentation for many existing electronic texts. The TEI guidelines as currently formulated contain few fixed requirements, but one of them is this: There must always be a document header, an in-file SGML tag that provides 1) a bibliographic description of the electronic object one is talking about (that is, who included it, when, what for, and under which title); and 2) the copy text from which it was derived, if any. If there was no copy text or if the copy text is unknown, then one states as much. Version 2.0 of the Guidelines was scheduled to be completed in fall 1992 and a revised third version is to be presented to the TEI advisory board for its endorsement this coming winter. The TEI itself exists to provide a markup language, not a marked-up text.

Among the challenges the TEI has attempted to face is the need for a markup language that will work for existing projects, that is, handle the level of markup that people are using now to tag only chapter, section, and paragraph divisions and not much else. At the same time, such a language also will be able to scale up gracefully to handle the highly detailed markup which many people foresee as the future destination of much electronic text, and which is not the future destination but the present home of numerous electronic texts in specialized areas.

SPERBERG-McQUEEN dismissed the lowest-common-denominator approach as unable to support the kind of applications that draw people who have never been in the public library regularly before, and make them come back. He advocated more interesting text and more intelligent text. Asserting that it is not beyond economic feasibility to have good texts, SPERBERG-McQUEEN noted that the TEI Guidelines listing 200-odd tags contains tags that one is expected to enter every time the relevant textual feature occurs. It contains all the tags that people need now, and it is not expected that everyone will tag things in the same way.

The question of how people will tag the text is in large part a function of their reaction to what SPERBERG-McQUEEN termed the issue of reproducibility. What one needs to be able to reproduce are the things one wants to work with. Perhaps a more useful concept than that of reproducibility or recoverability is that of processability, that is, what can one get from an electronic text without reading it again in the original. He illustrated this contention with a page from Jan Comenius's bilingual Introduction to Latin.

SPERBERG-McQUEEN returned at length to the issue of images as simulacra for the text, in order to reiterate his belief that in the long run more than images of pages of particular editions of the text are needed, because just as second-generation photocopies and second-generation microfilm degenerate, so second-generation representations tend to degenerate, and one tends to overstress some relatively trivial aspects of the text such as its layout on the page, which is not always significant, despite what the text critics might say, and slight other pieces of information such as the very important lexical ties between the English and Latin versions of Comenius's bilingual text, for example. Moreover, in many crucial respects it is easy to fool oneself concerning what a scanned image of the text will accomplish. For example, in order to study the transmission of texts, information concerning the text carrier is necessary, which scanned images simply do not always handle. Further, even the high-quality materials being produced at Cornell use much of the information that one would need if studying those books as physical objects. It is a choice that has been made. It is an arguably justifiable choice, but one does not know what color those pen strokes in the margin are or whether there was a stain on the page, because it has been filtered out. One does not know whether there were rips in the page because they do not show up, and on a couple of the marginal marks one loses half of the mark because the pen is very light and the scanner failed to pick it up, and so what is clearly a checkmark in the margin of the original becomes a little scoop in the margin of the facsimile. Standard problems for facsimile editions, not new to electronics, but also true of light-lens photography, and are remarked here because it is important that we not fool ourselves that even if we produce a very nice image of this page with good contrast, we are not replacing the manuscript any more than microfilm has replaced the manuscript.

The TEI comes from the research community, where its first allegiance lies, but it is not just an academic exercise. It has relevance far beyond those who spend all of their time studying text, because one's model of text determines what one's software can do with a text. Good models lead to good software. Bad models lead to bad software. That has economic consequences, and it is these economic consequences that have led the European Community to help support the TEI, and that will lead, SPERBERG-McQUEEN hoped, some software vendors to realize that if they provide software with a better model of the text they can make a killing.

DISCUSSION

During the discussion that followed, several additional points were made. Neither AAP (i.e., Association of American Publishers) nor CALS (i.e., Computer-aided Acquisition and Logistics Support) has a document-type definition for ancient Greek drama, although the TEI will be able to handle that. Given this state of affairs and assuming that the technical-journal producers and the commercial vendors decide to use the other two types, then an institution like the Library of Congress, which might receive all of their publications, would have to be able to handle three different types of document definitions and tag sets and be able to distinguish among them.

Office Document Architecture (ODA) has some advantages that flow from its tight focus on office documents and clear directions for implementation. Much of the ODA standard is easier to read and clearer at first reading than the SGML standard, which is extremely general. What that means is that if one wants to use graphics in TIFF and ODA, one is stuck, because ODA defines graphics formats while TIFF does not, whereas SGML says the world is not waiting for this work group to create another graphics format. What is needed is an ability to use whatever graphics format one wants.

The TEI provides a socket that allows one to connect the SGML document to the graphics. The notation that the graphics are in is clearly a choice that one needs to make based on her or his environment, and that is one advantage. SGML is less megalomaniacal in attempting to define formats for all kinds of information, though more megalomaniacal in attempting to cover all sorts of documents. The other advantage is that the model of text represented by SGML is simply an order of magnitude richer and more flexible than the model of text offered by ODA. Both offer hierarchical structures, but SGML recognizes that the hierarchical model of the text that one is looking at may not have been in the minds of the designers, whereas ODA does not.

ODA is not really aiming for the kind of document that the TEI wants to encompass. The TEI can handle the kind of material ODA has, as well as a significantly broader range of material. ODA seems to be very much focused on office documents, which is what it started out being called-- office document architecture.


CALALUCA

The final speaker in this session, Eric CALALUCA, vice president, Chadwyck-Healey, Inc., spoke from the perspective of a publisher re text-encoding, rather than as one qualified to discuss methods of encoding data, and observed that the presenters sitting in the room, whether they had chosen to or not, were acting as publishers: making choices, gathering data, gathering information, and making assessments. CALALUCA offered the hard-won conviction that in publishing very large text files (such as PLD), one cannot avoid making personal judgments of appropriateness and structure.

In CALALUCA's view, encoding decisions stem from prior judgments. Two notions have become axioms for him in the consideration of future sources for electronic publication: 1) electronic text publishing is as personal as any other kind of publishing, and questions of if and how to encode the data are simply a consequence of that prior decision; 2) all personal decisions are open to criticism, which is unavoidable.

CALALUCA rehearsed his role as a publisher or, better, as an intermediary between what is viewed as a sound idea and the people who would make use of it. Finding the specialist to advise in this process is the core of that function. The publisher must monitor and hug the fine line between giving users what they want and suggesting what they might need. One responsibility of a publisher is to represent the desires of scholars and research librarians as opposed to bullheadedly forcing them into areas they would not choose to enter.

CALALUCA likened the questions being raised today about data structure and standards to the decisions faced by the Abbe Migne himself during production of the Patrologia series in the mid-nineteenth century. Chadwyck-Healey's decision to reproduce Migne's Latin series whole and complete with SGML tags was also based upon a perceived need and an expected use. In the same way that Migne's work came to be far more than a simple handbook for clerics, PLD is already far more than a database for theologians. It is a bedrock source for the study of Western civilization, CALALUCA asserted.

In regard to the decision to produce and publish PLD, the editorial board offered direct judgments on the question of appropriateness of these texts for conversion, their encoding and their distribution, and concluded that the best possible project was one that avoided overt intrusions or exclusions in so important a resource. Thus, the general decision to transmit the original collection as clearly as possible with the widest possible avenues for use led to other decisions: 1) To encode the data or not, SGML or not, TEI or not. Again, the expected user community asserted the need for normative tagging structures of important humanities texts, and the TEI seemed the most appropriate structure for that purpose. Research librarians, who are trained to view the larger impact of electronic text sources on 80 or 90 or 100 doctoral disciplines, loudly approved the decision to include tagging. They see what is coming better than the specialist who is completely focused on one edition of Ambrose's De Anima, and they also understand that the potential uses exceed present expectations. 2) What will be tagged and what will not. Once again, the board realized that one must tag the obvious. But in no way should one attempt to identify through encoding schemes every single discrete area of a text that might someday be searched. That was another decision. Searching by a column number, an author, a word, a volume, permitting combination searches, and tagging notations seemed logical choices as core elements. 3) How does one make the data available? Tieing it to a CD-ROM edition creates limitations, but a magnetic tape file that is very large, is accompanied by the encoding specifications, and that allows one to make local modifications also allows one to incorporate any changes one may desire within the bounds of private research, though exporting tag files from a CD-ROM could serve just as well. Since no one on the board could possibly anticipate each and every way in which a scholar might choose to mine this data bank, it was decided to satisfy the basics and make some provisions for what might come. 4) Not to encode the database would rob it of the interchangeability and portability these important texts should accommodate. For CALALUCA, the extensive options presented by full-text searching require care in text selection and strongly support encoding of data to facilitate the widest possible search strategies. Better software can always be created, but summoning the resources, the people, and the energy to reconvert the text is another matter.

PLD is being encoded, captured, and distributed, because to Chadwyck-Healey and the board it offers the widest possible array of future research applications that can be seen today. CALALUCA concluded by urging the encoding of all important text sources in whatever way seems most appropriate and durable at the time, without blanching at the thought that one's work may require emendation in the future. (Thus, Chadwyck-Healey produced a very large humanities text database before the final release of the TEI Guidelines.)

DISCUSSION

HOCKEY prefaced the discussion that followed with several comments in favor of creating texts with markup and on trends in encoding. In the future, when many more texts are available for on-line searching, real problems in finding what is wanted will develop, if one is faced with millions of words of data. It therefore becomes important to consider putting markup in texts to help searchers home in on the actual things they wish to retrieve. Various approaches to refining retrieval methods toward this end include building on a computer version of a dictionary and letting the computer look up words in it to obtain more information about the semantic structure or semantic field of a word, its grammatical structure, and syntactic structure.

HOCKEY commented on the present keen interest in the encoding world in creating: 1) machine-readable versions of dictionaries that can be initially tagged in SGML, which gives a structure to the dictionary entry; these entries can then be converted into a more rigid or otherwise different database structure inside the computer, which can be treated as a dynamic tool for searching mechanisms; 2) large bodies of text to study the language. In order to incorporate more sophisticated mechanisms, more about how words behave needs to be known, which can be learned in part from information in dictionaries. However, the last ten years have seen much interest in studying the structure of printed dictionaries converted into computer-readable form. The information one derives about many words from those is only partial, one or two definitions of the common or the usual meaning of a word, and then numerous definitions of unusual usages. If the computer is using a dictionary to help retrieve words in a text, it needs much more information about the common usages, because those are the ones that occur over and over again. Hence the current interest in developing large bodies of text in computer-readable form in order to study the language. Several projects are engaged in compiling, for example, 100 million words. HOCKEY described one with which she was associated briefly at Oxford University involving compilation of 100 million words of British English: about 10 percent of that will contain detailed linguistic tagging encoded in SGML; it will have word class taggings, with words identified as nouns, verbs, adjectives, or other parts of speech. This tagging can then be used by programs which will begin to learn a bit more about the structure of the language, and then, can go to tag more text.

HOCKEY said that the more that is tagged accurately, the more one can refine the tagging process and thus the bigger body of text one can build up with linguistic tagging incorporated into it. Hence, the more tagging or annotation there is in the text, the more one may begin to learn about language and the more it will help accomplish more intelligent OCR. She recommended the development of software tools that will help one begin to understand more about a text, which can then be applied to scanning images of that text in that format and to using more intelligence to help one interpret or understand the text.

HOCKEY posited the need to think about common methods of text-encoding for a long time to come, because building these large bodies of text is extremely expensive and will only be done once.

In the more general discussion on approaches to encoding that followed, these points were made:

BESSER identified the underlying problem with standards that all have to struggle with in adopting a standard, namely, the tension between a very highly defined standard that is very interchangeable but does not work for everyone because something is lacking, and a standard that is less defined, more open, more adaptable, but less interchangeable. Contending that the way in which people use SGML is not sufficiently defined, BESSER wondered 1) if people resist the TEI because they think it is too defined in certain things they do not fit into, and 2) how progress with interchangeability can be made without frightening people away.

SPERBERG-McQUEEN replied that the published drafts of the TEI had met with surprisingly little objection on the grounds that they do not allow one to handle X or Y or Z. Particular concerns of the affiliated projects have led, in practice, to discussions of how extensions are to be made; the primary concern of any project has to be how it can be represented locally, thus making interchange secondary. The TEI has received much criticism based on the notion that everything in it is required or even recommended, which, as it happens, is a misconception from the beginning, because none of it is required and very little is actually actively recommended for all cases, except that one document one's source.

SPERBERG-McQUEEN agreed with BESSER about this trade-off: all the projects in a set of twenty TEI-conformant projects will not necessarily tag the material in the same way. One result of the TEI will be that the easiest problems will be solved--those dealing with the external form of the information; but the problem that is hardest in interchange is that one is not encoding what another wants, and vice versa. Thus, after the adoption of a common notation, the differences in the underlying conceptions of what is interesting about texts become more visible. The success of a standard like the TEI will lie in the ability of the recipient of interchanged texts to use some of what it contains and to add the information that was not encoded that one wants, in a layered way, so that texts can be gradually enriched and one does not have to put in everything all at once. Hence, having a well-behaved markup scheme is important.

STEVENS followed up on the paradoxical analogy that BESSER alluded to in the example of the MARC records, namely, the formats that are the same except that they are different. STEVENS drew a parallel between document-type definitions and MARC records for books and serials and maps, where one has a tagging structure and there is a text-interchange. STEVENS opined that the producers of the information will set the terms for the standard (i.e., develop document-type definitions for the users of their products), creating a situation that will be problematical for an institution like the Library of Congress, which will have to deal with the DTDs in the event that a multiplicity of them develops. Thus, numerous people are seeking a standard but cannot find the tag set that will be acceptable to them and their clients. SPERBERG-McQUEEN agreed with this view, and said that the situation was in a way worse: attempting to unify arbitrary DTDs resembled attempting to unify a MARC record with a bibliographic record done according to the Prussian instructions. According to STEVENS, this situation occurred very early in the process.

WATERS recalled from early discussions on Project Open Book the concern of many people that merely by producing images, POB was not really enhancing intellectual access to the material. Nevertheless, not wishing to overemphasize the opposition between imaging and full text, WATERS stated that POB views getting the images as a first step toward possibly converting to full text through character recognition, if the technology is appropriate. WATERS also emphasized that encoding is involved even with a set of images.

SPERBERG-McQUEEN agreed with WATERS that one can create an SGML document consisting wholly of images. At first sight, organizing graphic images with an SGML document may not seem to offer great advantages, but the advantages of the scheme WATERS described would be precisely that ability to move into something that is more of a multimedia document: a combination of transcribed text and page images. WEIBEL concurred in this judgment, offering evidence from Project ADAPT, where a page is divided into text elements and graphic elements, and in fact the text elements are organized by columns and lines. These lines may be used as the basis for distributing documents in a network environment. As one develops software intelligent enough to recognize what those elements are, it makes sense to apply SGML to an image initially, that may, in fact, ultimately become more and more text, either through OCR or edited OCR or even just through keying. For WATERS, the labor of composing the document and saying this set of documents or this set of images belongs to this document constitutes a significant investment.

WEIBEL also made the point that the AAP tag sets, while not excessively prescriptive, offer a common starting point; they do not define the structure of the documents, though. They have some recommendations about DTDs one could use as examples, but they do just suggest tag sets. For example, the CORE project attempts to use the AAP markup as much as possible, but there are clearly areas where structure must be added. That in no way contradicts the use of AAP tag sets.

SPERBERG-McQUEEN noted that the TEI prepared a long working paper early on about the AAP tag set and what it lacked that the TEI thought it needed, and a fairly long critique of the naming conventions, which has led to a very different style of naming in the TEI. He stressed the importance of the opposition between prescriptive markup, the kind that a publisher or anybody can do when producing documents de novo, and descriptive markup, in which one has to take what the text carrier provides. In these particular tag sets it is easy to overemphasize this opposition, because the AAP tag set is extremely flexible. Even if one just used the DTDs, they allow almost anything to appear almost anywhere.

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