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The "Loo k and Fee l" o f an Ebook: Co ns ide ra t ions inInterface Design

Ruth WilsonCentre for Digital Library ResearchUn iv e r s i t y o f S t r a th c l y d e

G l a s g o w , U K+44 (0 )141 548 370 5ru th.m.wUson@strath,ac.uk

ABSTRACTThis paper asks, "How should an electronic textbook look andfeel?" The results of the Visual Book and the WEB Bookexperiments, both o f which address this question, are discussed,and the EBONI (Electronic Book ON-sc reen Interface) Project'sevaluations involvin g students and lecturers in UK HigherEducation arc outlined. It is proposed that, in terms of the on-screen appearance of information, certain aspects of the paperbook metaphor should be retained and that text should be mademore "scannable " to suit the electronic medium. In terms of thelook and feel of the physical object, issues such as displaytechnology, size, weight and ergonomics should be taken intoaccount. These considerations will form the basis of EBON I'sbest practice guideline s for designing electronic textbooks.Keywordselectronic books, electronic textbooks, evalua tion1. INTRODUCTIONAt the most basic level, an electronic book is just a series of bits,a string of Is and 0s which require to be encoded in order tobecome meaningful words and sentences. It is how these bitsare presented and packaged that makes a book a readable,desirable product. "Look and feel" has become an issue ofcentral importance to ebook industry stakeholders, and the roleof designer is now firmly established as a critical link in theebook production chain. The excitement surrounding the launchof prototype "electronic paper" which shows electronic text onthin plastic sheets "ju st like paper" testifies m this [ 14], as doesthe investment by Microsoft in ClearType technology [10] forits reader soi~vare, which attempts to recreate the experience ofreading ink on paper by tripling the resolution of text on screen.ExeBook have even trademarked the phrase, "The took and feelof the real book!"v~, for use in promoting their self-publishingservices [3].

Permission to make digital or hard copies of all or part of this work forpersonal or classroom use is granted without fee provided that copies arenot made or distributed for profit or commercial advantage and thatcopies bear thi s notice and the full citation on the t~rst page, To copyotherwise, or republish, to post on servers or to redistribute to lists,requires prior specific permission and/or a fee.SAC 2002,Macirid, Spain 2002 ACM 1-58113-445-2/02/03...$5.00.

In answering the question, "How should an ebook look andfeel?", the wants and needs of users are paramount. As Nielsennotes, "Users have an in finite potential for interpreting userinterface design in new and unexpected ways ... You simplymust perform some kin d of user testing as part of your interfaceevaluation" [I i]. Of course, requirements will vary according tothe type of book being used. Whereas novels arc readsequentially, from the first page to the last, textbooks tend to beconsulted rather than read, dipped in and out of in a non-linearmanner. Encyclopaedias, on the other hand, contain facts aboutmany diverse subjects and arc referred to for a number ofpurposes; again, their users will have a separate set of needs.Audience definition is, therefore, the first step in assessing the"usability" of an elec tronic book.EBONI (Electronic Books ON-screen Interface), based at theCentre for Digital Libra ry Research, Unive rsity of Strethclydc,and fimded under the JISC DNRR Prosyanun for Lear ning andTeaching [5], is investigating this issue of ebook interfacedesign with a specific audience in mind: students and Iceturersin UK Higher Education.2. R O L E O F T H E E B O N I P R O J E C TSpecifically, the project aims to: Evaluate the different approaches to the design o felectronic textbooks, and to ide ntif y whi ch styles andfeatures are most successful in enabling users to retrieve,qui ckl y and easily, the inform ation they require. Identify and report on the individua l requirements ofstudents and academics from different disciplines andbackgrounds in learning and teaching using electronic

textbooks. Compile and promote s set of best practice guidelines forthe publication of electronic textbooks, reflecting theusability requirements of the U K HE community.These objectives arc being achieved through a series ofevaluations of different kinds of electronic textbooks in anumber of subject areas in which users interact with the testmaterial and provide feedback through a number of channels, inorder for their needs to be determined.A specially developed "Ebook Evaluation Model" is beingimplemented in varying degrees by each of these experiments,which will ensure that the results of each experiment arecomparable at som e level [20]. This methodology comprisesvarious options for selecting material and participants and

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describes the different tasks and evaluation techniques whichcan be employed in an experiment. These range from simpleretrieval tasks measuring participants' ability to find informationin the material to "high cognitive skill" tasks set by lecturers tomeasure participants' unders tanding of concepts in the texts, andfrom Web-based questionnaires measuring subjectivesatisfaction to one-to-one interviews with participants discussingelements o f interacting with the test material in detail. As such,it ofte n comprehensive and wide-ranging methods formeasuring the "usability" ofebooks , incorporating traditional [Rconcepts such as accuracy of retrieval, as wall as measureswhich reflect the complex requirements of learners and teachersin Higher Education.Ebook interfaces can be considered to comprise twocomponents: the text of the book, and the technology used todisplay the text (hardware and peripherals surrounding a screen,enabl ing the reader to interact with the book). The constmctiooof both components impacts on the usabil ity of the book; thisgives rise to two main factors which are being addressed byEBONI in its ebeok interface evaluations" The on-screen appearance of information. The look and feel of the physical object or reading device.Outlined below are some of the design elements beingconsidered, driven by prior or current research which indicatestheir importance in terms of usability.3 . O N - S C R E E N A P P E A R A N C EThe importance of on-screen appemance in the dcsigu ofebookshas previously been the subject of the Visual Book [6] end theWEB Book [I 9] experiments, with two central themes emergingas fundamental to usability" The legacy of the paper book metaphor, and the wisdom ofadhering to this, where appropriate, in the construct ion of

the e lectronic bo ok. The different set of requirements ar ising when the readerinteracts with the new medium; in particular, the

effectiveness of presenting material electronica lly in short,scannable chunks rather than a long, linear flow of text.Both themes continue to be the focus of EBON i's studies.3 .1 A d h e r e n c e to t h e P a p e r B o o k M e t a p h o rThe Visual Book experiment compared a textbook in paper andelectronic formats, and found that the book metaphor plays acrucial role in the definition of guidelines for the design ofelectronic books [7]. These should consider that an electronicbook has to resemble, be consis tent with, and work according tosome or all aspects of the b o o k metaphor with no ambiguities,conflicts, inconsistencies or confusion. Therefore: The page metaphor should be respected. That is, the pageshould be treated as a visual space where information can

easily be found end scanned. The logical structure of the book has to be considered.Tables of contents and indexes are essential features.These cannot simply be replaced by search facilities whose

complexity makes the reading process morn confusing forthe user. The book template has to be used strictly to presentinformation which is book related, and not any other kindof material, as the result would be a hetemganous system

w h i c h would confuse users. Titles, pagination and typographical aspects have to bedesigned carefidly to enhance text readability, Visual clues have to be adapted to exploit the potential ofthe medium where the book is published.That readers approach texts in c lecUronic fornmt withexpectations inherited from their experience with paper bookshas been confirmed in EBONi' s studies to date. As one readernoted alter reading a text on s handheld device, "It did n't feellike ! was reading a book. The fact that it was an electronicdevice rather than a traditional book with s cover and pagessomehow seemed to me to take something away from theexperience". Results of EBONI' s evaluations so far highlightthe importance of the following aspects o f the book metaphor: "opening" an electronic book should be as quick and easy aprocess as opening a paper book. Where a portion of thetext has already been read, navigating to this point in the

book should be possib le quickly or immediately. Indications of a reader's progress through the book shouldbe accurate and visible.In addition, one feature of reading a paper book has beenidentified as capable of improvement by the electronic medium.Some readers feel thst the action of turning pages slows downthe reading process, and that alternative methods of movingthrough a book offered on electronic devices, such as turningwheels and pressing keys or buttons, increase the speed at whichthey read the book. One participant in EBONrs experimentscommented, "In turn ing a paper page you lose momentum,albeit for a second or two. i di dn' t find this at all with theebook." Another noted, '*The abili ty to change pages by usingyour thumb on the wheel meant that yofi could quickly movethrough a story without breaking your stride".3 .2 S e a n n a b i l i t yin his Atertbox for July 26, 1998, Jakob Nietsen suggests that,in order to be a success, an electronic text should not simplymimic its paper counterpart [13]. He believes that the newmedium inevi tably involves the reader in a different way andthat much more powerful us er experiences can be achieved bydeviating from a linear flow of text. in particular, increasing the"scannability" of a text through use o f extra headings, largetype, bold text, highlighted text, bulleted lists, graphics andcaptions, can have a direct influence on its usabili ty [ 12].This theory was applied in the WEB Book experiment, in whichthe original, very plain electronic version of Chapter Five of CJ.can Rijsbergcn's "Information Retrieval" [15] was compared toa revised, scannable version of the chapter [16]. in the originalversion, each version of ~he chapter is allocated a separate webpage and text is organised in a linear way so that users have tokeep scrol ling down until they reach the end o f the chapter.

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Figure 1, Original version of chapterHyperlinks are used to provide some basic functions: movingfrom one chapter to the next, fi'om the table of contents to thebeginnin g of chapters, end from citations to bibliographicreferences (see Figure I ). In the revised version, the chapter wasdivided between ten separate web pages according to sub-headings in the original text, a chapter contents page providedlinks to each section, and more hypedinks were used to aidnavigation between the sections. Extra headings, coloured andsized, were inserted in the text in order to dividc it into smaller,more digestible chunks, diagrams were centred, key words andphrases were coioured red to call attention to important pieces oftext, and lists were indented, their numbe rs or bulle ts alsocoloured red (see Figure 2) [8].Users of the original version of the chapter disliked the designof the pages. One user described it as flat and not veryappealing; another noted that the ba ckground of the pages madethe formulae difficult to read; and a third found the layout of thetext distracting: 'Who text used was very turgid, and combinedwith the plain web design, it made it hard to concentrate on theinformation being sought". A lack of user-friendliness was alsocommented on.Users of the revised version, on the other hand, made positiveremarks about the page design, commenting that the table ofcontent s for the chapter made navig ation very easy, and that theuse of white space made the text look neat and "clean" and madeit easy to concentrate. However, one responden t thought thatthe use of colour to highlight keywords in the revised versionwas confusing, finding it unclear which items were hyperlinksand which were not. Another noted that the width of the lines oftext, spanni ng from one edge o f the screen to the other, made thetext diffficuh to read. The probl em of having to sc ro l l up anddown to see the different diagrams and equations was alsopointed out: "It is far easier to compare two different equations

on paper than scrolling up and down or opening and resizidifferent windows for c omparison" [9].U s e r s of the revised version made 150% fewer errors on tasthan users of t he original version, and use rs of the revisversion reported 4g% higher subjective satisfaction than usersthe original ve~i on, Overall usability scores for the twversions of the site show that, compared to the control versiothe revised version is 92% better.The results of EBONI's early experiments, in particular tevaluations of three e-textbooks in psychology, support thefindings, with participants appreciating use o f a few colours, bdisliking overuse of colour: "Too man y bright colours... Lay the colours". Long pages of unbroken text were felt to confusing and difficult to read, while use of chapter tables contents, headings and hyperlinks was found to aid navigatiIn the words of one user, "Index and chapter headings were veclear and well laid out ... It was fairly easy to navigate arouthe structure to find relevant areas".Therefore, unde r the "sca nnability" heading, several more ebointerface design considerations emerge: Tables ofc onte nts for individual chapters, as well as for whole book, aid navigation and can make it easier to fiinformation on specific topics. Navigation icons ahyperlinks can enhance structure and ~si st users in moviaround the book.m Page layout is important. Short pages with short chunkstext interspersed with images and diagrams can increintake of information. Sophisticated use of" whi te spacpage borders (as opposed to long lines of text stretching width of the screen), section headings and indentballoted lists can increase users' ability to scan material.

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Care fu l use o f a f ew co lo urs c an p ro v id e a co n s is ten t"s ty le " en d d raw a t t en t io n to k ey wo rd s en d p h rases ; use o fto o man y co lo urs c an b e d i s t r ac tin g .Diagrams en d fo rmulae sh o u ld b e p o s i t io n ed so th a t th eya re ea s i ly co mp arab le .

4 . L O O K A N D F E E L O F T H E P H Y S I C A LOBJECTOn-screen design, therefore , is a crucia l fac tor in the success ofe lec t ro n ic b o o k s , an d exp ec ta t io n s in h e r i t ed f ro m read in g o np ap e r mus t b e co n s id e red a lo n gs id e th e co n s t ra in t s an dcap ab i l i t i e s a r i s in g f ro m p resen t in g in fo rma t io n in d ig i t a lfo rmat , in o rd e r fo r usab i l i ty to b e max imised . EBO NIcontinues to investigate these issues in deta i l so that userexp ec ta t io n s, r equ i remen ts an d d es i re s c an b e a sce r tain ed , an d aco mp reh en s ive se t o f e - t ex tb o o k o n -sc reen d es ign gu id e l in esco n s t ruc ted .Dur in g Summer 2001 , th e p ro jec t a l so co n d uc ted re sea rch in toth e seco n d fac to r a f fec t in g eb o o k usab i l i ty : th e h a rd waresur ro un d in g th e t ext , wh ich en ab le s th e use r to in te rac t wi th th eb o o k . in p a r t i cu la r , five p o r tab le d ev ices a re b e in g eva lua ted b ylec tu rers an d re sea rch e rs a t th e Un ive rs i ty o f S t ra th c ly d e . A t th et ime of writ ing, th is research is in the early s tages, but feedbackin d ica te s seve ra l d es ign e lemen ts th a t c an en h an ce o r d e t rac tFro m th e exp e r ien ce o f r e ad in g o r c o n su l t in g an e lec t ro n ic b o o k .in terms of d isplay , technolo gy, resolution, glare , contrast ,b r igh tn ess an d b aek i igh t in g h ave p ro vo k ed co mmen t , w i th th eab i l i ty to r e ad un d e r a va r ie ty o f l igh t in g co n d i t io n s c i t ed a s ap r io r i ty . On e use r co m p la in ed th a t th e sc reen was d i f f i cul t toread un le ss th e l igh t in g co n d i t io n s we re p e r fec t , wh i le an o th e r

co mmen ted th a t , "At t imes th e sc reen co u ld b e d i f f i cu l t to r e adb ecause o f sun l igh t , c aus in g th e r ead e r to ad jus t p o s i t io n in g . O na p ack ed b u s o r t r a in th i s p ro ved an n o y in g an d ve ry d i f fi cu l t ".Dev ices wi th b ack l i t s c reen s , h o weve r , r e ce ived p ra i se fo rsu rp ass in g th e fun c t io n a l i ty o f p ap e r b o o k s , a t l e a s t in te rms o fa l lo win g th e usc r to r e ad in th e d a rk .Th e b u i ld o f th e d ev ices , e sp ec ia l ly th e i r s ize , we igh t an df rag il i ty , i s a l so th e sub jec t o f co n ce rn . Wh en i t co mes toe lec t ro n ic b o o k s , s ize ma t te rs . Sma l le r , l igh twe igh t d ev ices a reco mp l im en ted o n th e i r p o r tab i l i ty ( "Th e eb o o k i s sma l l en d l igh tso I co u ld ca r ry i t eve ry wh ere in my p o ck e t o r b ag") , b ucc r i t i c i sed fo r h av in g sc reen s wh ich a re to o sma l l to r e adco mfo r tab ly ( "A b igge r sc reen migh t b e an imp ro vemen t , i f th eo ve ra l l size o f th e d ev ice co u ld b e k ep t a s i t i s ") . Co n ve rse ly ,th e b u lk an d we igh t o f l a rge r d ev ices i s co n s id e red ad isad van tage , b u t th e s ize o f th e i r d i sp lay s i s ap p rec ia ted . Th isp a rad o x was co mmen ted o n b y o n e use r wh i le eva lua t in g th elargest of the test device s, the S ol, Boo k [18] '. "[ i t] rea l ly ne edsto b e mad e a lo t l igh te r /mo re p o r tab le . Ho weve r , h av in g used aPa lm I wo u ld say th a t th e l a rge r fo rma t i s much mo re ' r e ad e r -f r i en d ly ' . So [ guess y o u a re l e f t w i th a d i l emma - h o w d o y o up rese rve th e s ize / fo rma t b u t mak e i t mo re p o r tab le?"Ergo n o mic a sp ec ts a l so p ro vo k e co mmen t , w i th th e ab i l i ty toh o ld eb o o k h a rd ware co mfo r tab ly in o n e h an d co n s id e red ap o s i t ive f ea ture . Th e Hewle t t -Pack a rd Jo mad a 5 48 [4] , inp a r t i cu la r , r e ce ived p o s i t ive f eed b ack fo r b e in g easy to h o ld ,wh i le o n e use r o f th e Ro ck e t eBo o k [1 7] co mp la in ed th a t , "Th ed ev ice i t s e l f was qu i te b u lk y an d h eavy . So me e f fo rt h ado b v io us ly b een p u t in to th e e rgo n o m ics o f th e d ev ice , b u t i t jus td id n ' t f e e l r igh t . 1 fo un d my se l f co n s tan t ly sh in i n g i t fro m h an dto h an d " . In ad d i t io n , th e f r ag il i ty , o r l a ck o f ro b us tn ess , o f

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ebook ha rdw are i n com par i son t o pape rbacks o r ha rdbacks i sthought o f as a drawback, with users comment ing that thedel ica te nature o f dev ices const ra in usage.I n su m m ary , e a r l y f eedback f rom EB O N I ' s ev a lu a t i ons o fpor table reading devices points towards the fol lowing e lementsas worthy o f a t tent ion when designing for usabi l i ty: Display tech nolo gy should be high resolu t ion, wi th highcontras t and minimal g lare . Backl ight ing can increase

por tabi l ity , in tha t i t enables tex t to be read in po or l ight ingconditions. F inding the optimum size of eboo k hardware is a quest ionof balancing l ightness and p or tabi l i ty against leg ibi li ty oftex t on screen. Ebo ok hardware should be designed for comfor t , wi th theabi l i ty to hold a dev ice easi ly in one hand considered anadvantage. The nu m ber and d iv e r si t y o f s i tu a t ions i n w h ich ebooks canbe read can be const ra ined when devices are del ica te orfragile.5 . CO N CL U SIO N SPast and present research, therefore , h ighl ights a number ofelements whic h shou ld be considered when designing interfacesfor electronic textbooks. "Lo ok and fee l" play a crucial role inal lowing users to read and use tex t in e lec t ronic form as much asthey did and do wi th informat ion on paper ; thus, i t i s notsurpr is ing that gu idel ines for the product ion of good e lec t ronicbook s wi l l have to take in to a ccoun t these issues re la ted to s tyle ,

[ayout and ergono mics.EB O N I a im s t o de f ine heu r i s t i c r o l e s f o r t he p rodu c t i on o f"goo d" and "readable'" electronic textbooks by closely observingreaders' reactions to them. These rules, or best pracdceguidelines, will comprise the results of all EBONI'sexper iments , and wi l l be sent to re levant organisa t ions in ear ly2002, target ing publ ishers o f e lec t ronic mater ia l , l ibrar ies andmuseums involved in dig i t i s ing col lec t ions, and in teres tedpar t ies in the HE co mmun i ty in genera l , in addi t ion, they wiLLbe avai lable f rom the project Web s i te [2] , together wi th anexample of a tex t on which they have be en implemented.EBONi welcomes feedback a t a l l s tages, and in teres ted partiesare inv i ted to jo in the project mai l ing l i s t [1] .6 . A C K N O W L E D G E M E N T SThank s to Kei th van R i jsbargen for h is k ind pe rmission to usesc r eenaho t s o f " I n f o rm a t ion R e t r iev a l" .7 . RE FE RE N CE S[ i ] EB ON I mailing list . To join, follo w the instructions at:h t tp: / /www.j iscmai l .ac .uk/ l is ts /open-eboni .html[2] EB O N [ ( E l ec t ron i c B ooks O N -sc reen I n te r face ).h t ip : / /eboni.cdlr.strath .ac.uk/[3] ExeB ook Se lf Publ isher 1 .0. h t tp: / /www.exebook .com/[4] Hewlett-Packard Jo rnads 54 0 series.

h t l p : / /w w w . h p . c o m / j o r n a d a / p r o d u c t s /5 4 0 /

[ 5 ] J I SC (Jo in t I n f o rm a tion Sys t em s C om m i t t ee ) D N ER(Dist ribu ted Nat iona l Elect ronic Resource) Pro gramme forL e a r n in g a n d T e a c h in g . h t t p : / / w w w . j i s c . a c . u k / d n e r /

[ 6 ] L andon i , M . The V i su al B ook sys t em : A s tu dy o f th e u se o fv isual rhetor ic in the design of e lec t ronic book s. Glasgow:D epa r tm en t o f In f o rm a t ion Sc i ence , U n iv e r s it y o fSt ra thclydc (P hD Thesis) ( ! 997)[ 7] L a n d o n i , M . a n d G i b b , F . T h e r o l e o f v i s ua l r h e t o ri c

i n t h e d e s i g n a n d p r o d u c t i o n o f e le c t r o n i c b o o k s : t h ev i su a l b o o k . T h e E l e c t r o n i c L i b r a r y 1 8 ( 3 ) 1 9 0 -2 0 1[8] Lando ni , M., Wilson, R . and Gibb, F . From the VisualB ook t o t he WEB B ook : t he im por t ance o f g u od des ig n .F our t h E uropean Conf erence on R esearch an d A dvanc edTechnology or Digi tal L ibraries (ECDL 2000) , L isbon ,Por tugal , ! 8 -20 Septemb er (2000)[9] Lando ni , M., Wilson, R . and Gibb, F. Loo king forg u ide l i nes f o r t he p rodu c t i on o f e l ec t ro n i c t extbooks .Onl ine Informat ion Review. 25 (3) (2001)ht tp: / /www.usei t .com/aler tbo~980726.html[ i 0 ] Micro sof t C learType.h t t p : /I w w w . m i c r o s o f t .c o m l t y p o g r a p h y l c l e a r ty p e J[ ! l ] M o l i c h , R . a n d N i e l s e n , J . I m p r o v i n g a h m n a n -

c o m p u t e r d i al o g ue , C o m m u n i c a t i o n s o f t h e A C M , 3 3( 3 ) (1 9 9 0 ) 3 3 8 - 3 4 8

[ 12 ] M orkes , J. and N ie l sen , J . C onc i se , SC A N N A B L E, andobject ive: ho w to wri te for the Web (1997) .h t t p : / / w w w . u s e i t . c o m / p a p e r e d w e b w r i t i n g / w r i t i n g . h t r n l

[ 13"[N ie l sen , J . E l ec t ron i c books - a bad i des. J akob N ie i sen ' sAler tbox . 26 Ju ly ( I 998) .[ 14 ] N ob le , ! . E -pape r m o v es a s t ep nea re r. B B C N ew s O n l ine .23 Apri l (200 l ) .h t t p : / / n e w s , b b c . e o . u k / h i / e n g l i s i d s c i / t e c h / n e w s i d 1 2 9

2 0 0 0 / 1 2 9 2 8 5 2 . s t m[1 5i va n Ri jsbergen, C ,J . Informat ion re t r ieval . 2 "dd. ( | 979) .h t t p :/ / w w w . d c s . g l a . a c . u k J K e i t h / P r e f a c e . h t m l[16 ] van R i jsbergen, CJ. Cha pter f ive ("search s t ra teg ies" ) ,Informat ion re t r ieval . 2" ed, (1979) .

h t t p : / / e b o n i . d i s . s t r a t h . a c . u l d m s c / i n d e x . h t m[17] R ocke t eB o ok P ro . See P l ane t eB ook f o r de t a il s:

h t t p : / / w w w . p l a n e t e b o o k . c o m / m a i n p a g e . a s p ? w e b p a g e id= l 5& TB TooU D -- - - 1 ! 15

[ 18 ] Sof tB ook R eade r . See P l ane t eB ook f o r de t a i ls :h t t p : / /w w w . p l a n e t e b o o k . c o m / m a i n p a g e . a sp ? w e b p a g e idffi 15 &T BTo ollDF FI l I i 6

[ 19 ] Wi lson , R . The im por t ance o f appea rance i n t he des ign o fWEB books . G lasg ow : D epa r tm en t o f i n f o rm a t ionScience, Un ivers i ty of St ra thclyd e (MS c Dins.) ( ! 999) .

[20 ] Wilson, R . and Landoni , M . Evaluat ing electronict ex tbooks : a m e thodo log y . F i f th Eu ropean C onf e rence onR esea rch and A dv anced Techn o log y f o r D ig it a l L ib r a r ie s(ECDL 2001) , Darmstadt , Germany, 4 -9 September 2001.

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