Colour in computer graphics: Lecture notes

BOOK REVIEWS

Color Appearance Models, by Mark D. Fairchild, Addi- books that are both authoritative and up-to-date. And evenamid the dustiest of material (e.g., in the colorimetryson–Wesley, 1998, 448 pp., $96.79 hardbackchapter) , there is some new spin. For example, of the1931 and 1964 CIE standard observers, Fairchild says,The modeling of color appearance is the most important

frontier in color science, because of the increasing de- ‘‘The differences are computationally significant, but cer-tainly within the variability of color-matching functionsmands for a standard way to transport colors among de-

vices on the Internet, and to achieve faithful rendition of found for either 27 or 107 fields’’ (p. 90).Chapter 4, on color-appearance terminology, is alsocolors in the new digital television. But modeling color

appearance is an arcane subject, prey to ambiguities of lucid, and disambiguates the terms brightness, lightness,colorfulness, chroma, and saturation. (Hue, I think, wasterminology, homegrown answers to general problems,

and a pervasive tendency of some to dismiss the entire already unambiguous.) Where similar terms can be con-fused, Fairchild uses simple equations to draw distinc-field as not worth the effort. It is, therefore, important

now for practitioners of color management to have in tions.There follows a surprisingly complete summary (Chap-hand a monograph that summarizes the needs, ap-

proaches, and benefits in a rather diverse field. Such a ter 5) on color-order systems, and then an effectivelyillustrated catalogue of color-appearance phenomenamilestone book is Color Appearance Models, by Mark

D. Fairchild. (Chapter 6) . Chapter 7 on viewing conditions sets thestage for an introduction to chromatic adaptation (ChapterPerhaps the greatest tribute I can pay to this book is

confessing the regret I felt when I thought I had lost my 8). It is here that we first see (in Figure 8–7) the structureof a model ( in this case, predicting appearance matchesreviewer’s copy. With mounting sadness, I recalled what

I had lost. Nowhere else is catalogued so completely or across adaptation states) . The structure is quickly filledlucidly the color-appearance models of the past 40 years: in Chapter 9 with several chromatic adaptation modelsCIELAB, CIELUV, Nayatani’s model, Hunt’s model, (von Kries, Retinex, Nayatani, Guth, and Fairchild) , andGuth’s ATD model, LLAB, RLAB, ZLAB, and CIE- then the scene changes to the more general notion ofCAM97 (s and c, replete with a Web address to consult a color-appearance model (Chapter 10), in which thefor updates) . Nowhere else are models addressed so even- coordinates have absolute perceptual significance as wellhandedly: in the middle of the book is a catalogue of as color-matching status. Fairchild uses CIELAB andmodels, each one (call it ‘‘X’’) allocated sections on CIELUV as simple examples of such models, the formerobjectives and approach, input data, adaptation model, connected with the Von Kries chromatic adaptation viaopponent-color dimensions, perceptual dimensions, in- a ‘‘wrong von Kries transform’’ (i.e., in the basis X , Y ,verse model, phenomena predicted, and (most provoca- Z rather than in the basis of the receptors L, M, S). [Itively) ‘‘Why not just use Model X?’’ Nowhere else are wish Fairchild had also traced out the connection betweensuch models compared so precisely with such different CIELUV and Judd’s 1940 model1—both of which effectformulations as color-order systems and chromatic-adap- adaptation by subtracting the white chromaticity. Perhaps,tation theories. How could I function professionally in the in the future, an historical connection as well as a formalnext few months without my copy of Fairchild’s book? one can be made in this regard.]Fortunately, the book turned up within 24 hours, and I Chapters 11–14 catalogue the models mentioned in thedecided to keep better track of it. second paragraph of this review, and Chapter 15 deals

The book begins with a motivational introduction, with with tests of the models (presented pictorially and nota list of visual effects whose explanation is not obvious just through data figures) . Chapter 16 introduces the ap-without a model of color appearance. Fairchild offers plications of color-appearance models in fields outsideshort explanations, or ‘‘clues,’’ for these effects, one by color management (i.e., to assess color rendering, colorone. These explanations are self-contained, and give an differences, and metamerism).idea of what a color-appearance model is supposed to do. Then follows a true highlight of the book. Chapter 17 is

Next, the book launches into an accelerated (but readily a masterpiece in describing how to use a color-appearanceunderstandable) set of three chapters on human color vi- model in a color-management context (a problem of sa-sion, psychophysics, and colorimetry. Where detail neces- lient importance) . First, the chapter discusses the use ofsarily must be left out, Fairchild refers to reviews and such a model in device-independent color reproduction—

which requires that the model be run forward to a device-independent perceptual space, and then inversely to new

q 1998 John Wiley & Sons, Inc. device coordinates. Next, it describes how the Interna-

248 CCC 0361-2317/98/040248-08 COLOR research and application

/ 8a1c$$bkrv 06-30-98 17:13:54 crras W-Color Res

tional Color Consortium generalized the notion to achieve of contrast sensitivity functions. Such properties are notseen again until Section 7.1 (Configuration of the viewingindependence from viewing conditions as well as from

device contingencies. Nowhere is there a more authorita- field) , in which the spatial dependencies are boiled downto at most four sets of tristimulus values, and the temporaltive description.

Finally, there is a short chapter on the future course of dependencies are boiled down to a single ‘‘degree ofadaptation’’ parameter. In most of the color-appearanceevents (e.g., the prospect of a single standardized color-

appearance model) , followed by an Appendix that de- models, a single ‘‘equivalent surround’’ tristimulus is theonly allowed spatiotemporal dependence. These simpli-scribes one such model whose ratification is imminent

(CIECAM97s) and some of its relatives (CIECAM97c fications are made in the interests of computational tracta-bility, but it should be realized what is lost. Contrastand ZLAB).

In general, one appealing aspect of the book is the sensitivities of the visual system to chromatic and lumi-nance patterns, in the presence of various backgroundauthor’s willingness to be repetitive in the interests of

clarity. Many of the color-appearance models are derived patterns, are the basis of most visual psychophysics, allof which is quite germane to color appearance.from other such models, which in turn make use of chro-

matic-adaptation models described earlier in the text.Rather than surrender to the temptation to refer to earlier

Tristimulus-Value Unitstext, Fairchild repeats the equations, in a way that is (forthe most part) readily turned into computer code. [I note The dimensions (and units) of tristimulus values are

even more of a headache than I had indicated two yearsbelow a significant exception to this rule with respect tosome of the input dimensions.] ago.2 In absolute colorimetry, tristimulus values are given

the dimensions of lumens/m2 (as Fairchild implies on pp.Besides the lucidity of the prose, one should also notethe author’s adept use of graphics and color. This applies 85–87 by specifying the spectral power distribution as a

radiance) , but the data inputs to the models are mostto everything from demonstrations of color-induction ef-fects ( including the now-famous Color White’s Illusion) often in cd/m2 (luminance units) . The transition between

these dimensions, rarely discussed anywhere, is numeri-to color-coding certain data figures. A particularly goodexample is in Section 15.7, ‘‘A pictorial review of color cally easy but conceptually nontrivial: 1 m2 of a planar

light source emitting 1 lumen of luminous flux producesappearance models.’’ Here, a color image is comparedwith the images predicted to match with that image under 1 cd of luminous intensity (per steradian of solid angle

subtended by the measuring device) , but only when thedifferent conditions of chromatic adaptation. The figuresgive easily grasped indications of good vs. bad model emitter is Lambertian and the viewing direction is normal

to the emitting surface.behavior: for example, a model that predicts greater re-quired contrast under more intense illumination is clearly A similar difficulty besets relative colorimetry. Fair-

child’s definition of relative colorimetry (p. 87), whichnot right.Although Fairchild has written an outstanding book, it applies only for reflected spectral power distributions,

multiplies each tristimulus integral by 100 and dividesserves a specific purpose: to lead a reader who is literatein electronic imaging as quickly as possible from color it by the luminance integral of another spectral power

distribution—from a perfect reflecting diffuser. However,phenomena to current color-appearance models. The bookis neither an historical tract nor a scholarly review of in television (an important application area for color-

appearance models) the ‘‘relative quantity’’ is divided bybasic vision-science data (e.g., the vision ‘‘data’’ figuresrarely have references) . Nor is the book a way to learn the maximum producible value, and is not multiplied by

100. Because the inputs to all the color-appearance mod-about the framework of modern imaging standards (e.g.,such terms as JPEG and NTSC are undefined). Finally, els are in absolute units, this problem is not so important

in Fairchild’s book, although it can still produce misun-metrologists will not find in this book an explanation ofthe precision to which certain model constants are written. derstandings.

In his descriptions of the various color-appearanceRemembering this focus will allay readers’ frustrations.However, even a novice (who is familiar with engineering models, Fairchild handles the units adeptly and clearly.

Nayatani’s model, some of whose inputs are in lux andmathematics) can gain an understanding sufficient forintelligent selection and use of the models. in relative luminance factor (with the factor of 100 de-

fined on p. 87), are rationalized to cd/m2 at the outset,I now must raise a few issues that can be viewed asproblems with the field, not with the book itself. Fairchild to ease comparison with other models. In dealing with

Guth’s model, which has various ambiguities starting withhas served us excellently by describing the field clearlyenough to cast these issues into high relief. the definition of a troland in the Judd system (where no

candela is defined), Fairchild assumes without apologythe units cd/m2 in the input (X , Y , Z ) values. These are

Spatio-Temporal Properties.very good decisions, although leaving the reader withwell justified uneasiness about the field.Spatial and temporal properties of color vision are in-

troduced in Chapter 1 (end of Section 1.5) , in the form Fairchild is not so careful about units in describing the

249Volume 23, Number 4, August 1998


chromatic-adaptation models prior to incorporating them and its progenitors relies predominantly on asymmetricmatching experiments inherited from the Bradford chro-in full color-appearance models. A reader with questions

at this stage should refer to the later chapters, where the matic-adaptation part of the model. There is nothingwrong with such limited tests, so long as matches (equiva-chromatic-adaptation models find homes within color-ap-

pearance models. There the units are correctly attributed. lencies) determined by the adaptation model are not dis-turbed by other parts of the color-appearance model. ButThe one color-appearance model that does not receive

due attention to units is CIECAM97s, probably because the color-appearance models based on the Bradford trans-form (including CIECAM97s) contain just such distur-the model was late-breaking news at press time. Rest

assured that the tristimulus dimensions are cd/m2 for this bances. It is bewildering that agreement of data with theBradford transform could be a sign that such data aremodel, as for all the others.inconsistent with appearance models that contain theBradford transform. Fairchild does not discuss validation

Guidelines for Consistent Use of CIECAM97sof CIECAM97s, but he does praise the model. I hope thereader will deal with this praise advisedly, and (in theThe terminology of CIECAM97s and its progenitors,

which is adopted by Fairchild, is very misleading. Central future) look critically at the model tests to make sure thatthey are testing the right model.to CIECAM97s is the Bradford–Hunt model of chromatic

adaptation, in which there are two adaptation states: test Perhaps voicing these remarks has undone any profes-sional advantage I may have gained by finding Fairchild’s(source) and reference. As Fairchild explains (p. 378),

the reference state is characterized by ‘‘tristimulus values book after I lost it. Anyway, I recommend that anyoneinterested in color management or in quantifying colorof the reference white, in the reference conditions (usually

taken to be the equal-energy illuminant) .’’ One is led by appearance buy and read Fairchild’s book as soon as pos-sible. It is an indispensable guide during a foray into thethat terminology to believe that CIECAM97s performs a

complete appearance transformation from test to refer- wilderness of color-appearance models.ence conditions—both being ontologically equivalentstates that could be occasioned by real lights. As a result, MICHAEL H. BRILLwe get the impression that the model can be used entirelyin the forward direction, with no inverse necessary even 1. D. B. Judd, ‘‘Hue, saturation, and lightness of surface colors with

chromatic illumination,’’ J. Opt. Soc. Am. 30, 2–32 (1940).in the careful context of Chapter 17.2. M. H. Brill, ‘‘Do tristimulus values have units?’’ Color Res. Appl.This impression is completely false. The ‘‘reference’’

21, 310–313 (1996).state is disqualified as a possible test state, because themodel equations do not have the same form when testand reference labels are reversed. The ‘‘reference condi-

Visual Explanations: Images and Quantities, Evidencetion’’ is just a formal internal state of the model visualand Narrative, by Edward R. Tufte, Graphics Press,system, and one has to come out again through the inverseBox 430, Cheshire, CT, 1997, 151 pp., hardcover,transform to predict an appearance match between actual$45.00. ISBN 0 961 3921 2 6viewing conditions. Furthermore, in order for the model

to give unique predictions, the reference state must al-The author, Edward Tufte, is a Yale University professor,ways, not just ‘‘usually’’, be chosen the same—equalwho teaches statistical evidence, information design, andenergy if you must.interface design. He has written seven books, and this isTo Fairchild’s credit, he does not further reinforce thethe third one he also designed and published himself.reference-state problem by the statement (in the CIE-These three books have won sixteen awards for contentCAM97s documentation) that ‘‘For some practical appli-and design. They are not books for an artist to pick upcations it is necessary to be able to operate the model inexpecting examples of charts to illustrate statistics, evenreverse.’’ A more accurate statement, and also in keepingthough all three books are beautifully designed and dowith Fairchild’s Chapter 17, would be: ’’For any color-contain many illustrations. Tufte’s goal is problem solv-management application (and also for some others) it ising through intelligent, visual analysis of a situation.necessary to operate the model in reverse.‘‘

This book begins, ‘‘Our thinking is filled with assess-In view of this problem, I exhort: Read Chapter 17ments of quantity, an approximate or exact sense of num-before trying to use any of the color-appearance models.ber, amount, size, scale. In scientific work, both order-Then, in using anything based on the Bradford transform,of-magnitude reasoning and precise measurements aretake the ‘‘reference condition’’ jargon with a grain ofpersuasive. How are such quantities represented in visualsalt.expressions of ideas, experience, evidence? How are mov-ing images, photographs, diagrams, maps, and charts to

Model Tests

Although Chapter 16 catalogues a number of tests ofq 1998 John Wiley & Sons, Inc.color-appearance models, the validation of CIECAM97s

250 COLOR research and application


be scaled and labeled? And what makes images quantita- sures would not have prevailed over credible evidenceagainst the launch, for many other flights had been de-tively eloquent.’’

A large proportion of business decisions are based in layed in the past for good reasons. Had the correct scat-terplot or data table been constructed, no one would havetables, charts, and graphical presentations. This includes

the briefings the Pentagon gives to the White House. The dared to risk the Challenger in such cold weather.’’It is worth noting that his previous book, Envisioningselection of the data and the accuracy and clarity of its

presentation is vital to good decisions. Tufte believes that Information, also published by Graphics Press in 1990,contains an intelligent chapter on the use of color insince reliable information display is so important, the

individual who designed a presentation should be named. graphics, as well as many other examples of graphicsused to elucidate information.He is careful to name the source for all the graphics used

as illustrations and, when possible, the individual whoplanned and drew them. JOY TURNER LUKE

On almost every page are examples, some as early asthe 16th Century, that illustrate the successful, or unsuc-cessful, presentation of concepts and data. Several have Michel-Eugene CHEVREUL. Un savant, des cou-glued-on flaps that the reader looks under to see another leurs! Coordinated by Georges Roque, Bernard Bodo,version of the image. These examples include charts, pho- and Francoise Vienot. Published by the Museum d’His-tographs, paintings, and crude line drawings. Tufte is toire naturelle, Paris, and the Societe EREC (Etudes etmore interested in the clear delineation of a concept than Realisations de la couleur) , Puteaux, France, 1997, 278the graphic skill of the illustrator. He has contempt for pp., 16.5 cm 1 24 cm, softbound, FF 180. In French,most newspaper graphics, which appear simple and clear with a 6-page abstract in English.but sometimes distort information.

The book itself is a beautiful presentation. Its efficient One hundred and three years! This exceptionally long lifedesign allows captions and footnotes to be placed in a gave Michel–Eugene Chevreul an outstanding scientificspacious margin next to the illustration or text to which and historical stature. Chevreul, born in August 1786,they refer. Unfortunately, since books are also acknowl- started his scientific career in 1810 upon entering theedged where they are mentioned in the text, there is no Museum d’Histoire Naturelle, where he worked for 80bibliography at the end of the book where all the books years. Known first for his work in inorganic chemistry,and papers referenced can be seen. Like many books mainly about the nature of fatty materials, this laboratorypublished by authors without the discipline of an editor, man was able to apply his knowledge to the technologythe book is self-indulgent as well as creative. Tufte never of dyes and to the problems of colour perception. Asuses one word if three would do. A random example is Director of the department of dyeing techniques at thethe sentence, ‘‘When consistent with the substance and Manufacture Nationale des Gobelins, in Paris (France)in harmony with the content, information displays should when he was 38 years old, he applied his principles ofbe documentary, comparative, causal and explanatory, work and analytical method to the study of colour. Hequantified, multivariate, exploratory.’’ Each modifier retired 59 years later. A wonderful celebration organizedadds meaning to the sentence but pages of similar senten- for his centenary in August 1886 gave him extraordinaryces make slow reading. He also tends to make a strong fame. Chevreul died three years later, in April 1889.point and then beat it to death. This fascinating study about Chevreul was developed

These indulgences are overcome by the important is- and coordinated by the team of Georges Roque, Bernardsues Tufte raises about the type of thinking necessary to Bodo, and Francoise Vienot. Thanks to the lectures givenconstruct graphics that assist in solving problems. An in November 1989 for the celebration of the hundredthexample is his discussion of the drawings Dr. John Snow anniversary of his death, at the Museum d’Histoire na-used both to pinpoint the contaminated pump that caused turelle, the book is an attempt to give a survey of thisthe London cholera epidemic in 1854, and then to con- outstanding career. The works of Chevreul about fattyvince others to close the pump. Tufte also shows graphs, materials was not a part of this celebration. A meetingconstructed from the same data, that would have disguised was held the same year at Angers, Chevreul’s city ofthe source of the disease. birth, about the lipochemistry.

He contrasts this example of graphics that helped to This interesting book presents a set of 22 articles, 278solve a problem with an instance when graphics critical pages, related to various fields of Chevreul’s activity.to a major decision were inadequate. Tufte shows the These articles are published with an interesting set of 85tables and charts that were reviewed on January 28, 1986, pictures, drawings, and photographs, about two-thirds ofwhen the decision was made to launch the Challenger which are printed in color. The cover page shows anspace shuttle, even though the temperature was lower than extraordinary portrait of Chevreul at the age of one hun-for any previous launch. Seven astronauts died when theO-rings failed and the shuttle exploded. Tufte outlines all

q 1998 John Wiley & Sons, Inc.the pressures to launch, but concludes, ‘‘But these pres-



dred, taken in August 1886 by the famous artist and pho- many interesting details of the scientific mind of Chevreultographer Felix Nadar.* This portrait is extracted from and give new information about the discovery of radioac-one of the first ‘‘interviews’’ given on this occasion. Sev- tivity.eral other photographs taken the same day are also in- The second part contains six articles related to the workcluded in the book. The last cover page gives a reproduc- of Chevreul about colour perception. J. D. Mollon, in ation of a chromatic circle from Chevreul. very fine article ‘‘Chevreul’s vision theory in the nine-

The book content has three main parts. The first one teenth-century context,’’ gives an interesting analysis ofis devoted to ‘‘Chevreul, the laboratory man and the man the ideas of Chevreul about colour vision. He describesof one method.’’ The second one, certainly the most re- the chromatic hemispherical space of Chevreul, largelylated to the fields of interest of the readers of this journal, related to the dyeing industry, and explains how this spaceis ‘‘Colour vision and colour techniques.’’ The third and is redundant. Then he precisely describes the specific con-last one covers the field of ‘‘Chevreul and visual art his- tribution of Chevreul about the law of ‘‘simultaneoustory.’’ At the end of the work can be found an index of contrast.’’the authors’ names, and a general index, followed by ‘‘Parallels between some observations made by Che-elements of a bibliography of Chevreul’s publications and vreul and recent knowledge of the visual process,’’ byof publications dealing with Chevreul. Francoise Vienot, and ‘‘Coloured shadow phenomena

The work starts with a very good and interesting intro- within the law of contrast,’’ by Ph. Lanthony, examineduction, ‘‘Presentation,’’ written by G. Roque. He intro-

Chevreul’s work in relation to present knowledge aboutduces Chevreul, the man, his work and at the same time

the colour-vision processes.gives a presentation of the book. Then, in the first part,

D. Tabary, ‘‘NIMES, the new colour space,’’ and J. P.Raoul Chevreul the great-great grandson of the chemist,Longavesne, ‘‘From Chevreul to the new computing tech-recalls his life in ‘‘Michel-Eugene Chevreul, his life andnologies in the field of colour,’’ offer two articles relatedworks.’’ Bernard Bodo describes ‘‘About the exhibition:to recent work done at the Manufacture Nationale desOne hundred years ago, Michel-Eugene ChevreulGobelins, explaining how to adapt Chevreul’s work about1786–1889.’’ This evocation of some aspects of his sci-colour classification to present needs using data-pro-entific life includes many interesting drawings and pho-cessing and computing techniques.tographs.

The last five articles, ‘‘Chevreul between classicismSeven other articles are dedicated to various aspects ofand romanticism,’’ by J. Gage; ‘‘Simultaneous contrastthe mind of Chevreul. In ‘‘Chevreul and Berthelot,’’ J.and the visual arts,’’ by F. Molnar ; ‘‘Chevreul; contrastJacques reveals some comments written by Berthelot,and harmony in the art of gardening,’’ by G. Lecerf;who was Permanent Secretary of the Academie des Sci-and ‘‘How painters received Chevreul’s plates andences (France). This is an astonishing report about Che-ideas,’’ by G. Roque are all related to the third part ofvreul and about the peculiar nature of the relationship

between the two chemists. the book. They are devoted to Chevreul’s ideas aboutJ. L. Binet explains ‘‘Chevreul and biological colours, contrast and painting. This is a quite complex problem

or a missed date.’’ and these articles provide an interesting study of the‘‘Chevreul at the Manufacture des Gobelins’’ by C. question.

Gastinel-Coural, is a very interesting and well docu- The interest and originality of this work is mainly duemented article about Chevreul’s daily work at the Gobe- to the quality of all the contributors, who have broughtlins, where new documents are published for the first time; to this subject an extremely diversified set of well-docu-‘‘A look at Chevreul’s chemistry studies on dyeing,’’ by mented thoughts. Moreover, because Chevreul’s publi-G. Emptoz, and ‘‘About Chevreul’s 1848 chemistry stud- cations are not easily available, this book provides infor-ies made on fragments of antique wall paintings,’’ by B. mation in a very interesting way, frequently filling inGuineau, are related to Chevreul’s work on dyeing, dyes, some not well-known details. The articles also highlightand coloured pigments. the personality of Chevreul, an interesting result, be-

In the same first part we can read the article, ‘‘Che- cause most readers know very little about this famousvreul’s concern for method,’’ by M. Blondel-Megrelis. laboratory man.In this article, the author explains the main characters of

In conclusion, this is an important work, attractive andthe method described by Chevreul as an experimentalquite easy to read. Scientists will certainly be interestedmethod a posteriori. She gives an interesting set of Che-by this book, as well as all persons concerned with colourvreul’s quotations about his method.science. However, many other people will also appreciateIn ‘‘Chevreul and photography: a revealing theme ofreading about an outstanding man in a very rich scientificboth his scientific activity after 1847 and his place withinperiod in history.the scientific world,’’ J. Fournier and P. Fournier reveal

ROBERT SEVE* Felix Tournachon.



Colour in Computer Graphics: Lecture Notes, by Lin- round. Module 3A, Displays and Color Coding, followswith slides dedicated to various display technologies anddsay MacDonald, MacColour, Ltd., Derbyshire, U.K.,

PhotoCD Version: $195 (educational) , $275 (indus- the use of color in different applications. (This moduleis somewhat redundant with module 1C, but provides newtrial) , 35mm Slides Version: $295 (educational) , $440

(industrial) examples.) The next module (3B), Printing and Repro-duction, provides an overview of subtractive color mix-ing, color separation, half-toning, and several other practi-Colour in Computer Graphics is a set of 108 color slides

and accompanying lecture notes. The PhotoCD version cal issues that arise in color reproduction. Finally, Module3C, Human–Computer Interface, covers examples of thewas reviewed. It consisted of a PhotoCD containing the

images and 52 pages of lecture notes. The PhotoCD jewel use of color in a variety of computer interfaces includinga slide on text legibility that should be viewed by anyonecase and the lecture notes are all attractively mounted in

a loose-leaf binder. As an alternative to the PhotoCD preparing presentation slides.In terms of content, the quality of the images and ac-images, the set is also available as 35-mm slides. Further

information on availability, pricing, and content is avail- companying text is very high. The material is covered ina comprehensive manner with a very informative, inter-able at the author’s web site: »http: / /www.MacColour.

co.uk … . disciplinary style. This is further enhanced with the exten-sive listings of additional reading materials. The notes areThe slides and notes are organized in nine modules of

12 images each. The modules include: (1A) Human Color successful at reaching the targeted audience (undergradu-ate courses in a variety of disciplines) and concise enoughVision, (1B) Color Modeling and Specification, (1C) Us-

ing Color Effectively in Displays, (2A) Light and Reflec- to be very useful to instructors preparing lectures. Whilemost instructors would want to supplement the materialtive Media, (2B) Color in Art and Design, (2C) Psychol-

ogy and Perception, (3A) Displays and Color Coding, with their own viewpoints and insights, the notes providean excellent overview of what the author intended to com-(3B) Printing and Reproduction, and (3C) Human–Com-

puter Interface. The lecture notes include a paragraph municate with each slide. The instructor can then judgethis material and decide whether to use it directly, modifyaccompanying each slide with both a specific explanation

of the content as well as other interesting and related it, or toss it out completely. This kind of flexibility is anice feature of the way this set was put together.tidbits that would be useful in a lecture. In addition, each

module ends with a nicely annotated listing of suggested In terms of image quality, a number of the slides aredisappointing. Much of this stems from the process byreadings that include a range of textbooks, reference

works, monographs, and journal articles. which the PhotoCD was produced. Each of the imageswas scanned from a 35-mm slide and then stored on theThe first module (1A), Human Color Vision, includes

topics such as the anatomy and physiology of the visual CD. The PhotoCD format allows an easy preview of theimages at a low resolution and then they can be decodedsystem and some basic perceptual phenomena such as

simultaneous contrast and after-images. Module 1B, and used at five different resolutions ranging from192 1 128 pixels up to 3072 1 2048 pixels. The highestColor Modeling and Specification, features slides de-

picting various color-order systems and color spaces in resolution includes essentially all the information avail-able in a 35-mm frame and should be adequate for almostaddition to an overview of CRT display technology. The

next module (1C), Using Color Effectively in Display every user. This process does a nice job on pictorial im-ages, which represent less than half of this slide set. ManyTechnology, includes several examples of how color can

be used to enhance the communication of information in of the slides are presentation graphics, which suffer asignificant loss in quality when going through the processa variety of applications ranging from road maps to ordi-

nal plots of image data, to warning signs, to computer from digital original, to photographic transparency, backto digital files in the form of a PhotoCD. This particularinterfaces. The fourth module (2A), Light and Reflective

Media, covers topics such as illumination, color render- problem is heightened in approximately 15 of the slidesthat originated from material photographed from a CRTing, the spectrum, rainbows, diffraction, transmission, ab-

sorption, and reflection. Module 2B, Color in Art and display of digital information. Both the presentationgraphics and the ‘‘screen dumps’’ would be significantlyDesign, includes interesting example images from the

world of fine art, some examples of fundamental design better if the digital data had been encoded directly to theCD. Also, many of the PhotoCD images do not utilizeprinciples, and examples of designs that utilize color with

particular intent or effect. The next module (2C) on Psy- the full display dynamic range when decoded and requireadditional tone reproduction and color-balancing opera-chology and Perception includes examples of contrast

phenomena including two from the work of Albers, ad- tions to optimize display color quality. Of course, thosepurchasing the 35-mm slides would avoid this difficultyvancing and receding colors, discounting the illuminant,

chromatic adaptation, and the importance of image sur- at the significant cost of losing the flexibility of digitalfiles. Perhaps in a future edition (this is the second), theimages of digital origin might be more directly encoded

q 1998 John Wiley & Sons, Inc. to a CD format.



To further explore the range of material covered in this sketches of each of the slides on his web site, cited above.Anyone interested in these teaching materials shouldset, I would like to now highlight a few of my favorite

and least favorite images. My favorites include a picture check it out.of a rainbow, a famous chromatic-adaptation demonstra-tion, and a color-reproduction issue. The rainbow is par- MARK D. FAIRCHILDticularly interesting not just because it is a nice photo-graph, but because it appears over Newton’s birthplace

Publications Briefly Mentionedin Lincolnshire. The chromatic adaptation demonstrationis R. W. G. Hunt’s famous example in which a yellow J. Color Sci. Assoc. Jpn., Vol. 22, No. 1, 1998.pillow is covered with a piece of cyan filter in order toproduce a green pillow. In a second slide, the same cyan Foreword, A Horizon of Color Culture, by Kazuo Jo;filter is placed over the entire image resulting in a pillow Essays: Color gives you the richness of feelings, by Touruthat, once again, appears yellow. Beyond their compelling Ozeki; A Culture of Color, by Hiroko Uchida; The 32demonstration of chromatic adaptation, these slides are Colors on My Palette, by Atsuko Kawaguchi; and Digitalprecious for historical reasons. The color reproduction Archives of Fine Art, by Yuukou Horita.slide shows a computer user contemplating a color display Original Paper: An Investigation of the Development ofof a harbor scene that just happens to be identical to the Mandarin Color Terms in Berlin and Kay’s Theory of theharbor scene outside his office window. While the image Evolution, by Lu Ching-Fu.is a bit contrived, it prompts a wealth of very thought- Reports: Evaluation of Feelings of the Hyper-Sensitiveprovoking issues. toward Patterns—Comparison between the sexes— , by

A few of my least favorites include two images of Masayo Nakatani and Nobuko Suzuki; Report on 28thchromaticity diagrams and a plot of the cone spectral Annual Meeting; News from Kansai Branch; Mourningresponsivities. The first chromaticity diagram image Essey; News from Study Group on Color Design; CRAshows the 1931 xy diagram artistically filled in with a Abstracts; and The Minutes of the Executive Board ofrainbow of colors. This is just the type of image that is CSAJ 1997.routinely torn into several pieces during course lecturesto reiterate the point that a chromaticity diagram is notan appearance space, but rather a nominal scale of color

Proceedings of the CIE Symposium 1997 on Standardmatches. On the positive side, this slide provides a digitalmethods for specifying and measuring LED charac-original that can be repeatedly printed out to be torn upteristics, CIE x013-1997 Central Bureau of the CIE,in front of generations of future classes. The second chro-Vienna, Austria, 1997. pp. 85 $126 (list) ; $84 (mem-maticity-diagram image shows the color gamuts of a CRTbers) ISBN 3 900 734 85 2display and a printer projected onto the xy diagram.

Again, this diagram is colored in, but it also propagatesCurrently there is considerable effort within the LED in-the serious and all-to-common error of representing de-dustry and the communities who use LEDs to standardizevice gamuts in two dimensions, when they cannot beon LED characterization and measurement. CIE TC 2-34meaningfully interpreted without examination of all threeLED Measurements completed its report on the subjectdimensions of color space. The slide with a plot of the(published as CIE 127-1997 Measurement of LEDs) . Thecone responsivities has no technical problems, but I hadCIE 1997 Workshop and Symposium, held on 22–25to look at it several times and decode a higher resolutionOctober 1997 at the CIE Central Bureau, Vienna, Austria,version before I could find the blue cone responsivity,introduced the CIE recommendations on LED measure-since it was plotted using a thin blue line on a dark back-ments and dealt with the underlying radiometric, photo-ground. This is one of the very rare instances in whichmetric, and colorimetric measurements. Health aspects ofthe author forgot his own tips on legibility and effectiveLED radiation were also discussed.use of color!

The goals of the meeting were to introduce the recom-I am sure that another reviewer would pick completelymended CIE method for characterizing LEDs, to sharedifferent sets of favorite and least favorite slides for en-information on the technical content and status of projectstirely different reasons, and that is one of the beauties ofinvolving the characterization of LEDs, to identify areasthis set. It presents a wide variety of interesting andwhere existing/proposed industrial methods are divergentthought-provoking material in the interdisciplinary worldand to initiate discussion towards resolution, to identifyof color. Almost anyone who lectures on color will findareas requiring new technology or knowledge, and to rec-something of value in this set. I would not recommendommend needed activities of CIE and industry to providethis set as a standalone teaching tool for students; it re-the necessary solutions.quires the additional interpretation from an instructor or

a full textbook. While I wouldn’t suggest that anyone runout and buy this set sight unseen, the author has greatly

q 1998 John Wiley & Sons, Inc.simplified the decision process by posting thumbnail



Papers were read on the following subjects: new The present document updates and replaces Publication CIELED technologies; industrial measurements; safety is- 68-1986 ‘‘Guide to the lighting of exterior working areas.’’sues of LEDs and other light sources, eye hazards; The values published are based on illuminance concept.LED lighting products, the use of LEDs in modern The minimum to maximum ratio was introduced. Glarelighting applications; measuring new LED products, is limited by Glare Rating (GR). The values are ‘‘main-laboratory and industrial measurements; and LED tained’’ and determined to achieve efficient working con-measuring devices. ditions, safe movement, and traffic and safety/security of

The Proceedings contain the text of the 12 papers read people and property. Work areas are divided into twelveas well as a report on the roundtable discussions. sections and listed in the Application Tables.

Attention is focused on design values. Other topics,such as colour quality, maintenance, environmental as-pects, design, and measurement are only mentioned inGuide for lighting exterior work areas, CIE 129-1998this document. Detailed recommendations or standardsCentral Bureau of the CIE, Vienna, Austria, 1998 pp.

20 $66 list $44 (members) ISBN 3 900 734 87 9 should be sought in relevant CIE and ISO publications.



Documents

Colour in computer graphics: Lecture notes