How We Look At Photographs (JIS&T)

How We Look at Photographs as Indicated by ContrastDiscrimination Performance Versus Contrast Preference1

S Gershoni and H KobayashiDepartment of Information Science Graduate School of Science and Technology Chiba University

1-33 Yayoi-cho Inage-ku Chiba 263-8522 JapanE-mail sharon_gershonihotmailcom

Abstract Considering luminance contrast to comprise the buildingblocks of the photographic language we aimed to study the connec-tion between viewerrsquos contrast discrimination performance in black-and-white photographs with various contrast reproductions andtheir aesthetic appeal In a previous study we examined the viewerrsquosability to discriminate contrast increments applied to discrete re-gions of the characteristic curves of gray scales versus photographsof Ansel Adams The photographs belonged to three conceptual cat-egories portrait landscape and architecture Whereas contrastdiscrimination performance in gray scales was very poor in repro-ductions with altered contrast in the shadows a significant improve-ment in performance was observed in the photographs In thepresent study subjects performed a contrast preference evaluationtask in which the reproductions of the photographs were rated fortheir aesthetic appeal on a five-point scale The photographs werepresented in random order without indication as to which is theoriginal photograph Nevertheless the viewers showed a generalpreference for photographs with contrast reproductions similar to theoriginal The results suggest a match between the viewersrsquo and thephotographerrsquos preferences Moreover the preference decreasedsystematically with the contrast increment for all reproductions Thistendency seems to be independent of variations in category or spa-tial configuration The results are in line with the observed contrastdiscrimination performance and also consistent with the anchoringtheory and recent propositions of biologically based rules for artcreation and appreciation as manifestations of the function of thebrain copy 2006 Society for Imaging Science and TechnologyDOI 102352JImagingSciTechnol2006504320

INTRODUCTIONThe investigation of art as a means to understand the orga-nization of the visual brain was recently proposed by Zeki1

who drew the outlines of ldquoa theory of aesthetics that is bio-logically basedrdquo Ramachandran and Hirstein2 proposed uni-versal laws for artistic experience in relation to phenomenasuch as the peak shift effect and gestalt grouping principlesConsidering such suggestions led us to examine black-and-white photography as a case of art We chose the photo-graphs of Ansel Adams3 the founder of the ldquoZone Systemrdquo4

for tone control Assuming luminance contrast to comprisethe building blocks of the photographic language we exam-ined the connection between the viewersrsquo ability to discrimi-nate luminance contrast in black-and-white photographsand their aesthetic appeal

Early experimental studies in aesthetics used simple and

artificial stimuli After the pioneering work by Fechner in18765 measurements of the viewers moods for differentpatches of color were conducted by Wexner in 19546 andlater repeated by Eysenck78 using polygons etc Cross-cultural and cross-gender aesthetic studies originated withJahoda9 in 1956 and followed by many others One of theadvantages of using simple displays was the accuracy of ma-nipulation it allowed compared to the difficulty in achievingpictorial sameness between the reproduced stimuli and anartwork The conditions of pictorial sameness under whicha reproduction is aesthetically valuable as the original wereproposed in the transferability thesis10 But an opposing ar-gument stated that even pictorial sameness of a reproductiondoes not necessarily grant sameness in aesthetic value11

Thus the weakness of the early studies is that the aestheticresponse to simple artificial stimuli is likely to be weak asthe viewers generally do not regard simple displays as prettyespecially in the context of being participants in an experi-ment Moreover most people do in fact experience artthrough reproductions through art books and other mediaPhotography a reproduction system in its essence offersmore control over reproduction and better sameness thanany other medium of art Black-and-white photographs inparticular are a good source for faithful reproduction Theyrepresent subject properties as a relationship between thecorrelating values of luminance (not color) with only one-dimensional luminance gray scale Therefore while black-and-white photographs still carry the conceptual attributesas any other medium of art they are less complex to ma-nipulate in a controlled process

In a previous paper12 we reported the roles and inter-ferences of local and global visual processes in lightness per-ception of photographs with meaningful contents we exam-ined whether contrast discrimination is a response to spatialconfiguration properties of photographs or a function ofconceptual contents In three experiments we comparedcontrast discrimination performances of observers whenpresented with contrast increments applied to discrete tonalregions in gray scales versus several categories of black-and-white photographs of natural scenes In the first experimentobservers performed contrast discrimination in gray scalesusing rank-order tasks In the following two experimentsobservers performed contrast discrimination of photographsusing sorting tasks We found substantial differences in re-

1Presented in part at ISTrsquos NIP XXI Baltimore MD September 2005

Received Jun 3 2005 accepted for publication Oct 30 2005

1062-370120065043207$2000

Journal of Imaging Science and Technologyreg 50(4) 320ndash326 2006copy Society for Imaging Science and Technology 2006

320

sponse to contrast increments depending on where in thecharacteristic curve (ie shadow highlight or midtones)they were applied On the other hand we reported no sig-nificant effect of category (portrait landscape and architec-ture) In addition we found that low performances in theshadow region of gray scales significantly improved in pho-tograph which we related to the differences in configurationcomplexity We also reported differences in performance be-tween photographs of light and night scenes These resultsraised an assumption that the differences in spatial configu-ration complexity and not the conceptual content of thephotographs improved contrast detection performance

A possible explanation is provided by the ldquoanchoringtheory of lightness perceptionrdquo13 Photographs depictingnatural objects contain much more complex and articulatedinformation than gray scales thus local frameworks weighmore than global frameworks which results in improvedlightness constancy and better performance in contrast dis-crimination tasks These findings are also in line with recentpsychophysical measurements of threshold versus contrastfor images of natural scenes where image whitening yieldedlower contrast discrimination threshold than high contrastimages14

Since looking at photographs is a visual task involvingan aesthetic experience a question of interest is What is therelationship between the contrast discrimination reportedabove and the aesthetically preferred contrast reproductionof photographs Recent studies claimed similar to the resultsreported above that there is no effect of context such as poseand shape of objects on processes such as lightnessconstancy15 Opposing suggestions are that contextual infor-mation does affects processes such as global formperception16

According to this view one could expect contrast toinfluence the content of photographs and their aesthetic ap-peal Therefore the question asked in the present study wasabout the relationship between the conceptual content ofphotographs and their contrast preference

Moreover should there indeed be a common rule forboth execution of art and its appreciation then one couldexpect similarity in the preferences of viewers andphotographers1718 (see also Discussion) Therefore thisstudy examines the relationship between the preferred con-trast reproduction and the ldquooriginalrdquo (unaltered) reproduc-tion which may reflect on the photographerrsquos preferenceversus the viewer preference

EXPERIMENTStimuliEight black-and-white photographs from the ldquoPhotographsof the Southwestrdquo book by Ansel Adams19 were used asstimuli for the present study

1 ldquoSpanish Peaks Coloradordquo 1951 p 182 ldquoCanyon de Chelly National Monument Arizonardquo

1947 p 303 ldquoMoonrise Hernandez New-Mexicordquo 1944 p 554 ldquoNavajo Woman Wide Ruin Arizonardquo 1948 p 39

5 ldquoMaynard Dixon Painter Tucson Arizonardquo 1944 p16

6 ldquoMartha Porter Pioneer Woman Ordeville Utahrdquo1961 p 81

7 ldquoAdobe Dwellings Northern New-Mexicordquo 1958 p49 and

8 ldquoArches North Court Mission San Xavier del BacTucson Arizonardquo 1968 p 94

The photographs selected belong to three major themes inphotography Landscape (photographs Nos 1 2 and 3) Por-trait (Nos 4 5 and 6) and Architecture (Nos 7 8 and 9)These themes represent Ansel Adamsrsquo work in general andthe selected photographs are among his well-known and re-produced works It is important to note that photographsselected as stimuli were of various configuration complexi-ties articulation depth and tonal relationships etc

Stimuli Reproduction ProcessThe goal of the reproduction process was to alter the shadow(SH) highlight (HI) and midtone (MT) contrasts of theeight selected images An Epson GT-9700 flatbed scannerwas used to scan the book pages The scanning pixels-per-inch (ppi) was 400 The ppi was chosen to match the print-ing system output resolution (Lambda printing system seeexplanation below) For calibration of the reproduction sys-tem the density of a Kodak standard gray-scale and its re-production were measured using a Sakura PDA 8112 reflec-tion densitometer and plotted against each other to assure alinear relationship between the reflection densities

Image files for the various highlight midtone andshadow contrasts were generated using Adobe Photoshopreg

Curve function in the Adjustments menu The horizontalaxis of the curve graph represents the original brightnessvalues of the pixels (input levels) the vertical axis representsthe new brightness levels (output levels) The curve displayseither brightness values from 0 to 255 with the shadows onthe left or values from 0 to 100 with shadows on theright The default diagonal line shows that all pixels have thesame input and output values

In order to alter contrast two anchordrag points wereestablished on the diagonal line

1 to alter shadow contrasts XSH=75 YSH=75 2 to alter highlight contrasts XHI=25 YHI=25

and3 to alter midtone contrasts both highlight and shadow

anchor points were established XHI=25 YHI

=25 XSH=75 YSH=75

A 2 contrast increment for each of the reproduction setswas achieved by pulling the anchoring point in one of thefollowing directions

1 shadow XSH+2 =XSH+2 YSH+2 =YSHminus2 2 highlight XHI+2 =XHIminus2 YHI+2=YHI+2 and3 midtone XHI+2 =XHI+2 YHI+2=YHIminus2

XSH+2 =XSHminus2 YSH+2 =YSH+2

Gershoni and Kobayashi How we look at photographs as indicated by contrast discrimination performance

J Imaging Sci Technol 504Jul-Aug 2006 321

For each of the three sets of reproductions (ldquoHIrdquo ldquoSHrdquoand ldquoMTrdquo) contrast increment ranged between 2 and 10in steps of 2 named sample Nos 2ndash10 accordingly

The densities of the photographs are represented byKodak standard gray scale reproduction sets which weremeasured using a reflection densitometer and plottedagainst the original gray scale as shown in Figs 1(a) (HI andSH) and 1(b) (MT)

A total of 128 photographic prints were produced byLambda system using a conventional black-and-white silverprocess Lambda prints are made on a Durst Lambdaprinter which uses three colored lasers to expose traditionalphotographic media These prints have the advantage of us-ing the same rich red-green-blue (RGB) color space em-ployed by computer monitors In addition these prints arefree of dots since unlike inkjet printers the laser outputs arecontinuously modulated rather than switched on and offTheir 400 dpi resolution is comparable to 1200 dpi screenedoutput

ParticipantsThirty subjects male and female (in 31 ratio) aged between20 and 30 participated in the experiment 46 of the par-ticipants were either familiar with the photographer or re-ported to have previously seen the photographs used asstimuli

Illumination SourceThe light source was a Toshiba natural color evaluationlamp 5000 K 700 lux Light source was overhead with re-spect to the viewing area Observation distance and anglenot designated

ProcedureEach photograph and its reproductions composed a set of 16stimuli The stimuli were presented on a table in a rectan-gular arrangement of a random order of contrasts as shownin Fig 2 with no indication of the unaltered original photo-graph (OR) or any other standard

Participants were requested to evaluate the aesthetic ap-

Figure 1 a Characteristic curves for stimuli with 2ndash10 contrast increment in regions HI and SH bCharacteristic curve for stimuli with 2ndash10 contrast increment in region MT


322 J Imaging Sci Technol 504Jul-Aug 2006

peal of each sample according to a one-dimensional prefer-ence scale between 1 and 5 in which 1 is the lowestevaluationmdashldquomost dislikerdquo 2mdashldquodislikerdquo 3mdashldquoneither likenor dislikerdquo 4mdashldquolikerdquo and 5 is the highest evaluationmdashldquolikebestrdquo

ResultsEvaluation ratios on the 1ndash5 preference scale for the pho-tographs of each category (portraits landscape and archi-tecture) were separately calculated as a function of the toneregions (HI SH and MT) Within each region five contrastincrements of 2 were indicated as sample Nos 2ndash10 asshown in Fig 3 The graph shows that preference was high-est for OR and decreased systematically with contrast incre-ment in all regions (HI SH and MT) and all categoriesThis pattern of decreasing preference showed some varia-tions which could be dependent on either category varianceor the tone regions In order to investigate which of thesevariables accounted for the observed differences mean aver-age preferences were calculated for the categories and for theregions

The mean average preferences for categories were 290for portraits 288 for landscapes and 288 for architecture asshown in Fig 4(a) These results indicated that contrast pref-erence was similar across the different categories In order toconfirm these observations a two way analysis of variance(ANOVA) with categories (portrait versus landscape versusarchitecture) and contrast increments (OR vs 2 vs 4hellipvs10) as variables was conducted In this and all other sta-

tistical tests =005 and the 95 confidence interval wereused for significance The effect of category was not signifi-cant F2 58=005 p=089 This reflects that there was nodifferential effect of category over preference of contrastMoreover comparison between photographs within categorydid not show significant difference either F2 58=178p=0065 Mean average preferences for regions were 26 forHI 27 for MT and 31 for SH as shown in Fig 4(b) A twoway ANOVA with regions (HI vs SH vs MT) and contrastincrements (OR vs 2 vs 4hellipvs 10) as variables re-vealed that although the effect of regions over preference wasnot substantial it was significant F2 58=1194 with p00001

These results are in line with previous experiments inwhich the ability to perform contrast discrimination wasmeasured for the same stimuli (see Introduction) Therecontrast discrimination was not affected by category but de-termined by the discrete tonal regions in which contrast al-teration occurred In fact the present results show that thepreference pattern is an inversion of the contrast discrimi-nation pattern the higher the contrast discrimination ratiothe lower the preference

It is important to note that although contrast discrimi-nation ratio for MT was found to be significantly higherthan that for the other regions preference for MT was notthe lowest one could expect as shown in Fig 5 The figureshows the effect of tonal region (HI vs SH vs MT vs OR)over mean contrast preference

Paired comparisons of contrasts revealed that contrastpreference did not differ much between MT and HI regionsF1 58=214 p00001 On the other hand preferenceevaluation significantly increased in SH region F1 58=2174 p00001 In addition the mean average prefer-ence of SH was above ldquo3rdquo in the evaluation scale whereevaluation tends towards ldquolikerdquo while MT and HI were be-low the 3 where evaluation is already ldquodislikerdquo This finding

Figure 3 Average preference for stimuli 2ndash10 across the three categories and three regions

Figure 2 The arrangement of stimuli in the preference evaluation task



implies a greater degree of tolerance towards contrast incre-ments in the shadow regions of the photographs In suchcontrast reproductions the overall impression of the lighten-ing of the image For an image which seems to becomedarker there is a lower degree of tolerance Figure 6 showsthe differential effect of contrast increment (2 6 and10) over regions For 2 contrast increment preferencesat regions HI SH and MT are 359 360 and 355 respec-tively for 6 the preference of SH over the other regions is

already substantial 252 33 and 28 and the difference iseven greater for 10 increment 158 267 and 197

Preference for the OR was substantially higher than allother stimuli independent of category or tonal region Thatis although stimuli were displayed in a random order withno reference to the original photographs observersrsquo prefer-ence matched the preference of the photographer for allstimuli as shown in Fig 5 where mean average preferencefor OR is 39 and for SH MT and HI 31 274 and 26respectively Paired comparisons of contrasts confirmed thatpreference for OR was significantly higher than all otherstimuli F1 58=7719 p00001

DISCUSSIONThe purpose of this study was to investigate the aestheticappeal of contrast reproductions in black-and-white photo-graphs and the connection between contrast preference andcontrast discrimination performance

Results revealed an inverse and linear relationship be-tween contrast increment and contrast preference wherepreference decreased systematically with increment Alsocontrast preference seems to be independent of conceptualcontent but apparently also from spatial configuration char-acteristics Based on contrast discrimination results we ex-pected to find a connection between preference and regionsNevertheless a uniform preference pattern was observed for

Figure 5 A comparison between average preference of the unalteredphotograph OR and regions HI vs SH vs MT

Figure 4 a Average preference across categories reveals no significant difference b Average preferenceacross regions HI vs SH vs MT reveals significant difference



all photographs tested Results also revealed a match be-tween the photographerrsquos contrast preference manifested inhis choice of contrasts in the photographs tested and that ofthe viewer

One way of explaining these results is with the anchor-ing theory of lightness perception20ndash22 In mapping lumi-nance into a lightness scale the highest luminance is an-chored (assigned) to white and the rest of the values arescaled relative to it Other factors influencing anchoring arethe area rule and configural attributes of the image such asarticulation and insulation The compromise between theanchoring rules determines whether anchoring occurs in thelocal framework or the global framework While strong an-choring to local framework increases lightness constancywhen the global framework is stronger lightness constancydecreases and assignment to white is enhanced Perhaps asthe contrast in the shadow region increases insulation de-creases and the white areas grow bigger thus the photographis perceived as being lighter Therefore the decrease in light-ness constancy might be the reason for what seems to begreater tolerance to contrast increments in shadow regionsthan in highlights or midtones

In both experiments ie contrast discrimination per-formance and preference evaluation of photographs resultsreflected no influence of high vision processes such as theperceived depth of stimulus21 to influence perception of thebrightness of the pattern or the context effect23 also labeledldquoobject-superiority effectrdquo suggesting that the context ofoverall structure and form influences early processing suchas features extraction

Moreover the argument that viewers prefer shapes andarrangements which are most ldquoeffectivelyrdquo processed by ourvisual system2425 must also be reexamined in light of thepresent results This argument derived from a work that ex-amined the effect of orientation on the aesthetic appeal ofMondrianrsquos paintings The results in that work reflected amatch in the preferred orientation between the artist and theviewers This is in line with the match in contrast preferencereported in the present paper and also early experimentswith other mediums of art including also poetry and prose

where sentences from well known classical writers weremodified to impair the literary effect26ndash28 music where wellknown pieces were modified to major mode and minormode29 orientation in abstract paintings30 and other pic-ture alterations31

The explanation for the tendency to prefer certainshapes or arrangements (Mondrian) which are effectivelyprocessed was claimed to lie in the biological need to main-tain a certain level of stimulation of the visual system Likeother adaptive mechanisms the visual system is encouragedto function most effectively thus it prefers the more extremestimuli over the weaker ones (peak shift effect32)

According to this argument artists should prefer to cre-ate line art or solid-color rectangular arrangements such asMondrians and photographers should prefer high contrastfilm But in reality it is not so In fact even Mondrian is butone example out of the general art creation Even if Mon-drian was indeed gifted in the capability to intentionally cre-ate a faithful expression of the visual system does that makehis art therefore weigh more than other art works as amanifestation of the visual mechanisms If so that would bein contradiction with the above argument itself denying itsuniversal neurobiological ground according to which all artworks are manifestations of the brainrsquos mechanisms andconstraints33 If we all prefer the same shapes and orienta-tions then we should all have been making Mondrians withno variance throughout art history and no effect of culturalgeographical and historical conditions

If indeed the most extreme stimuli is the preferred oneby the visual system and has the highest appeal to us all thenthe results of the present experiment should have been thatthe greater the contrast increment the higher the preferenceevaluation In fact the results reflect that both photographerand viewer prefer the contrast of reproductions similar tooriginal and not the extremes

This leads to the suggestion that the match betweenartist and viewers in constrast reproduction preference ororientation preference are valid only within the context ofthe specific artworks and cannot be translated to other artworks

CONCLUSIONFurther investigation using eye movement tracker can an-swer questions relating to the effect of contrast alterationover meaningful details in photographs and the consequenteffect over fixation centers drifts and attention followingearlier studies34ndash37

ACKNOWLEDGMENTSThe authors wish to express their gratitude to M TsukadaHoriuchi Color Tokyo for printing and laminating the entirestimuli and supporting the research and to ProfessorMasako Jitsumori Chiba University for his extensive assis-tance in the data analysis

REFERENCES1 S Zeki Art and the Brain (Oxford University Press Oxford UK 2000)2 V S Ramachandran and W Hirstein ldquoThe science of artmdashA

neurological theory of aesthetic experiencerdquo J Conscious Stud 6 15ndash51

Figure 6 A comparison between average preferences at regions HI vsSH vs MT for stimuli 2 6 and 10 contrast increment



(1999)3 A Hammond ldquoAnsel Adams and the objectivismmdashMaking a

photograph with group f64rdquo History of Photography 22 169ndash178(1998)

4 I H Latour ldquoAnsel Adams The zone system and the California Schoolof Fine Artsrdquo History of Photography 22 147ndash154 (1998)

5 G T Fechner Vorschule der Asthetik (Breitkopf amp Hartels Leipzig1876)

6 L B Wexner ldquoThe degree to which colors (hues) are associated withmood tonesrdquo J Appl Psychol 38 432ndash435 (1954)

7 H J Eysenck ldquoAn experimental study of aesthetic preference forpolygonal figuresrdquo J Gen Psychol 79 3ndash17 (1968)

8 H J Eysenck and M Castle ldquoTraining in art as a factor in thedetermination of preference judgments for polygonsrdquo Br J Psychol 6165ndash81 (1970)

9 G Jahoda ldquoSex differences in preferences for shapes A cross-culturalreplicationrdquo Br J Psychol 47 126ndash132 (1956)

10 G Currie ldquoThe authentic and the aestheticrdquo Am Philosophical Q 22153ndash160 (1985)

11 J Elkins ldquoWhat are we seeing exactlyrdquo Art Bull 79 191ndash198 (1997)12 S Gershoni and H Kobayashi ldquoHow we look at photographsmdashAs

indicated by contrast discrimination performancerdquo J Soc InformationSci Technol Japan accepted

13 A Gilchrist and C Kossyfidis ldquoAn anchoring theory of lightnessperceptionrdquo Psychol Rev 106(4) 795ndash834 (1999)

14 C A Olman K Ugurbil and D Kersten ldquoEffects of image structure onperceived contrast and cortical activity in early visual areasrdquo J Vision3(9) 47a (2003)

15 C Ripamonti M Bloj R E Hauck K Mitha and D H BrainardldquoObject lightness constancy Effects of object pose and shaperdquo J Vision3(9) 295a (2003)

16 C Habak F Wilkinson Z Bernadette and H R Wilson ldquoContextualeffects in form perceptionrdquo J Vision 3(9) 354a (2003)

17 See Ref 118 R Latto D Brain and B Kelly ldquoAn oblique effect in aesthetics Homage

to Mondrianrdquo Perception 29 981ndash987 (2000)19 A Adams Photographs of the Southwest (New York Graphic Society

Boston MA 1976)20 A L Gilchrist ldquoPerceived lightness depends on perceived spatial

arrangementrdquo Science 195 185ndash187 (1977)21 A L Gilchrist ldquoWhen does perceived lightness depend on perceived

spatial arrangementrdquo Percept Psychophys 28(6) 527ndash538 (1980)22 See Ref 1323 N Weisstein and C S Harris ldquoVisual detection of line segments An

object superiority effectrdquo Science 186 752ndash755 (1974)24 See Ref 1825 R Latto ldquoThe brain of the beholderrdquo in Artful Eye edited by R L J

Gregory P Harris and D R Heard (Oxford University Press Oxford1995) pp 66ndash94

26 C Burt in How the Mind Works cited by I Gordon and C Gardner(Allen amp Unwin London 1933) ldquoResponses to altered picturesrdquo Br JPsychol 65 243ndash251 (1974)

27 E D Williams L Winter and J M Woods ldquoTest of literaryappreciationrdquo Br J Educ Psychol 8 265ndash284 (1938)

28 C V Valentine The Experimental Psychology of Beauty (MetheunLondon 1962)

29 K Havner ldquoThe affective character of major and minor modes in musicAm Psychol 47 103ndash118 (1935)

30 M S Lindauer ldquoThe orientation of form in abstract artrdquo Proc AmPsychological Assoc 4 475ndash476 (1969)

31 N C Meier The Meier Art Tests 2 Aesthetic Perception (University ofIowa Bureau of Educational Research and Service Iowa City IA 1963)

32 See Ref 233 See Ref 134 A L Yarbus Eye Movements and Vision edited by L A Riggs (Plenum

Press New York 1967) edited by R L Solso Cognition and the VisualArts (MIT Press Cambridge MA 1994) p 145

35 C F Nodine P J Locher and E A Krupinski ldquoThe role of formal arttraining on perception and aesthetic judgment of art compositionsrdquoLeonardo 26 219ndash227 (1993)

36 C F Nodine and H L Kundel ldquoPerception and display in diagnosticimagingrdquo Radio Graphs 7 1241ndash1250 (1987)

37 C F Nodine ldquoSearching for NINA 1987rdquo in R L Solso Cognition andthe Visual Arts (MIT Press Cambridge MA 1994) pp 143ndash147



sponse to contrast increments depending on where in thecharacteristic curve (ie shadow highlight or midtones)they were applied On the other hand we reported no sig-nificant effect of category (portrait landscape and architec-ture) In addition we found that low performances in theshadow region of gray scales significantly improved in pho-tograph which we related to the differences in configurationcomplexity We also reported differences in performance be-tween photographs of light and night scenes These resultsraised an assumption that the differences in spatial configu-ration complexity and not the conceptual content of thephotographs improved contrast detection performance

A possible explanation is provided by the ldquoanchoringtheory of lightness perceptionrdquo13 Photographs depictingnatural objects contain much more complex and articulatedinformation than gray scales thus local frameworks weighmore than global frameworks which results in improvedlightness constancy and better performance in contrast dis-crimination tasks These findings are also in line with recentpsychophysical measurements of threshold versus contrastfor images of natural scenes where image whitening yieldedlower contrast discrimination threshold than high contrastimages14

Since looking at photographs is a visual task involvingan aesthetic experience a question of interest is What is therelationship between the contrast discrimination reportedabove and the aesthetically preferred contrast reproductionof photographs Recent studies claimed similar to the resultsreported above that there is no effect of context such as poseand shape of objects on processes such as lightnessconstancy15 Opposing suggestions are that contextual infor-mation does affects processes such as global formperception16

According to this view one could expect contrast toinfluence the content of photographs and their aesthetic ap-peal Therefore the question asked in the present study wasabout the relationship between the conceptual content ofphotographs and their contrast preference

Moreover should there indeed be a common rule forboth execution of art and its appreciation then one couldexpect similarity in the preferences of viewers andphotographers1718 (see also Discussion) Therefore thisstudy examines the relationship between the preferred con-trast reproduction and the ldquooriginalrdquo (unaltered) reproduc-tion which may reflect on the photographerrsquos preferenceversus the viewer preference

EXPERIMENTStimuliEight black-and-white photographs from the ldquoPhotographsof the Southwestrdquo book by Ansel Adams19 were used asstimuli for the present study

1 ldquoSpanish Peaks Coloradordquo 1951 p 182 ldquoCanyon de Chelly National Monument Arizonardquo

1947 p 303 ldquoMoonrise Hernandez New-Mexicordquo 1944 p 554 ldquoNavajo Woman Wide Ruin Arizonardquo 1948 p 39

5 ldquoMaynard Dixon Painter Tucson Arizonardquo 1944 p16

6 ldquoMartha Porter Pioneer Woman Ordeville Utahrdquo1961 p 81

7 ldquoAdobe Dwellings Northern New-Mexicordquo 1958 p49 and

8 ldquoArches North Court Mission San Xavier del BacTucson Arizonardquo 1968 p 94

The photographs selected belong to three major themes inphotography Landscape (photographs Nos 1 2 and 3) Por-trait (Nos 4 5 and 6) and Architecture (Nos 7 8 and 9)These themes represent Ansel Adamsrsquo work in general andthe selected photographs are among his well-known and re-produced works It is important to note that photographsselected as stimuli were of various configuration complexi-ties articulation depth and tonal relationships etc

Stimuli Reproduction ProcessThe goal of the reproduction process was to alter the shadow(SH) highlight (HI) and midtone (MT) contrasts of theeight selected images An Epson GT-9700 flatbed scannerwas used to scan the book pages The scanning pixels-per-inch (ppi) was 400 The ppi was chosen to match the print-ing system output resolution (Lambda printing system seeexplanation below) For calibration of the reproduction sys-tem the density of a Kodak standard gray-scale and its re-production were measured using a Sakura PDA 8112 reflec-tion densitometer and plotted against each other to assure alinear relationship between the reflection densities

Image files for the various highlight midtone andshadow contrasts were generated using Adobe Photoshopreg

Curve function in the Adjustments menu The horizontalaxis of the curve graph represents the original brightnessvalues of the pixels (input levels) the vertical axis representsthe new brightness levels (output levels) The curve displayseither brightness values from 0 to 255 with the shadows onthe left or values from 0 to 100 with shadows on theright The default diagonal line shows that all pixels have thesame input and output values

In order to alter contrast two anchordrag points wereestablished on the diagonal line

1 to alter shadow contrasts XSH=75 YSH=75 2 to alter highlight contrasts XHI=25 YHI=25

and3 to alter midtone contrasts both highlight and shadow

anchor points were established XHI=25 YHI

=25 XSH=75 YSH=75

A 2 contrast increment for each of the reproduction setswas achieved by pulling the anchoring point in one of thefollowing directions

1 shadow XSH+2 =XSH+2 YSH+2 =YSHminus2 2 highlight XHI+2 =XHIminus2 YHI+2=YHI+2 and3 midtone XHI+2 =XHI+2 YHI+2=YHIminus2

XSH+2 =XSHminus2 YSH+2 =YSH+2




















































































How We Look At Photographs (JIS&T)

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Transcript of How We Look At Photographs (JIS&T)