The roles of color lightness and saturation in
inducing the perception of miniature faking
Kun Qian

Kayo Miura

Institute of Decision Sciencefor a Sustainable Society
Kyushu University
Fukuoka, Japanqk@kyudai.jp

Faculty of Human-Environment Studies
Kyushu University
Fukuoka, Japanmiurak@kyudai.jp

Abstract— The miniature faking effect is a perceptual
phenomenon where life-sized objects and landscape intilt-shift photographs are perceived to be miniature.
Previous studies have contributed to the generation ofminiature faking; these include blur (bokeh), camera
angle, vantage point, and perceived distance. Althoughcolor has also been considered to be a crucial factor ininducing the miniature faking effect, research based on
systematical manipulations of color attributes has notbeen conducted. In the present study, we conducted twoexperiments, namely, paper-based and display-based tocontrol the color lightness and saturation of two bird’seye view photographs. The results showed that the rated
miniature faking effect is dependent on alterations ofcolor lightness and saturation. Higher saturation,
whereas lower lightness was found to enhance theminiature faking effect. These results demonstrated thecrucial role of color in inducing the perception ofminiature faking and further provided new materials toexplore the general cognitive mechanism involved inminiature faking.

landscape are perceived to be miniature. Miniature
faking can be produced by special photography
techniques when using a tilt-shift lens or by the digital
post-processing of an ordinary photograph.
Consequently, it is also referred to as tilt-shift
miniaturization. A sample of such a photograph isdepicted in Fig. 1.

Keywords: Miniature faking; tilt-shift miniaturization;color; saturation; lightness; image processing;photography

I.
INTRODUCTION
The miniature faking effect, which is also referred
to as the diorama effect or diorama illusion, is aphenomenon related to the visual perception ofphotographs where real objects and life-sized

Several psychophysical inducing factors have been
revealed in previous studies so as to determine thereasons for miniature faking. Blur, also known as bokeh,
which linearly appears at the top and bottom of aphotograph, has been considered to be an essential
factor in miniature faking [1]. The effect of blur has
been explained from the perspective of distanceperception [1, 2, 3]. Camera angle, corresponding withvantage point, has been reported to be another factor
involved in miniature faking [4, 5]. Previous studies
have also revealed other factors such as depth
perception [3, 4], photograph size [4], and density ofobjects [5]. Besides the psychophysical factors noted
above, the role of color has also been indicated to be an
important factor in inducing the miniature faking effect[4, 5, 6]. In our previous investigation, factor analysis
revealed color to be a latent variable underlying theminiature effect [5]. An experimental manipulation on
color and blur also suggested that strengthened chroma
helped to induce a more enhanced miniature faking
effect [6]. However, as yet, no experiments involving
systematical manipulations on multiple color attributes
have been conducted. In the present study, we alteredcolor lightness and saturation to explore therelationship between different color attributes and theminiature faking effect.
II.

EXPERIMENT 1A. Methods
1) Participants
The participants in the experiment included 28adults (15 males and 13 females; 21–59 years old, mean
± SD age: 27.1 ± 9.3 years). All participants had normal
or corrected-to-normal visual acuity. They were
unaware of the purpose of the experiment.
2) Stimuli
Figure 1. An example of miniature faking. A
photograph of a real scene but perceived as a diorama.

978-1-5386-7512-0/19/$31.00 @2019 IEEE

Figure 2. Stimuli used in the experiments. A total of 24 stimuli were recreated based on two bird’s-eye viewphotographs with manipulations on saturation in four levels and lightness in three levels.
As shown in Fig. 2, two photographs with a bird’seye view of urban scenery in Japan were used asoriginal images in the experiment. It is noteworthy that
all the participants lived in Japan.

We manipulated each original image’s saturation onfour levels and lightness on three levels by using
TiltShift Generator, an Adobe AIR based image
processing software for recreating tilt-shift as well as
miniature faking effects on normal photographs. The

image processing was conducted by employing adesktop computer (VAIO, SONY, Japan).
Regarding the manipulation of saturation, weadjusted the saturation indicator in the software to +50,0 (original), -50, and -100 (turned to monochrome).
Furthermore, in relation to lightness, we adjusted thebrightness indicator to +50, 0 (original), and -50.
Consequently, 24 images, including the original images,
were created. We also used a linear blur filter with astrength value of +0.3 to 25% of the areas at the top andbottom of all the images by adjusting the vignetting
strength to a value of 0.3 to generate a miniature faking
effect. The size of the processed images was 1500 and2000 pixels in height and width, respectively. All 24
images were employed as stimuli in the experiment.

-50 saturations, and between +50 and -100 saturations
were significant (ps < 0.001); When the lightness wasenhanced (+50), the differences between +50 andoriginal saturations, between +50 and -50 saturations,and between +50 and -100 saturations were significant(ps < 0.001). When the lightness was diminished (-50),
the difference between +50 and -100 saturations was
significant (p < 0.01).

We printed the stimuli on A5-sized (148*210 mm)
white paper in RGB color mode by using a four-color
inkjet printer. The stimuli were printed at the center ofthe paper, with a size of 128*170 mm. We printed one
stimulus onto each sheet of paper; hereinafter referred
to as the stimulus sheet.
3) Procedure
The participants were asked to view the stimulus
sheet and rate the miniature faking effect on a 7-point
scale, ranging from “do not look like miniature” (1) to“look like miniature” (7). The 24 stimulus sheets wereeach tested randomly without repetition. No time limits
for the participants’ viewing or rating of the photos
were imposed. However, they were instructed torespond intuitively, without any thoughtful judgment.
B. Results
We conducted a three-way within-participant
analysis of variance (ANOVA) on the mean rated
values of the miniature faking effect by employing thefactors, stimulus, saturation, and lightness. The resultsof ANOVA revealed a significant main effect ofsaturation [F(3, 81) = 10.310, p < 0.0001] as well as asignificant interaction between saturation and lightness[F(6, 162) = 2.947, p < 0.01]. However, the main effectof stimulus [F(1, 27) = 1.308, p = 0.263], the main
effect of lightness [F(2, 54) = 1.284, p = 0.285], theinteraction between stimulus and saturation [F(3, 81) =0.433, p = 0.730], the interaction between stimulus andlightness [F(2, 54) = 2.388, p = 0.101], and theinteraction among three factors [F(6, 162) = 1.01, p =0.421] were not significant. Tests of simple maineffects on the significant interaction between saturationand lightness showed that the effect of saturation was
significant for all lightness conditions [Original: F(3,243) = 6.089, p < 0.001; +50 lightness: F(3, 243) =14.598, p < 0.0001; -50 lightness: F(3, 243) = 2.682, p< 0.05]. However, the effect of lightness was
significant only when the saturation was enhanced[Original: F(2, 216) = 1.618, p = 0.201; +50 saturation:F(2, 216) = 5.259, p < 0.01; -50 saturation: F(2, 216) =0.436, p = 0.647; -100 saturation: F(2, 216) = 1.742, p= 0.178]. Multiple comparisons were conducted byusing Ryan’s method [7]. Regarding the significant
main effect of saturation, there were significant
differences between +50 saturation and the original,
between +50 and -50 saturations, and between +50 and-100 saturations (ps < 0.01). Regarding the significant
interaction between saturation and lightness, when thelightness was original, the differences between +50 andFigure 3. Results of Experiment 1. The mean rated
miniature faking effects are shown as functions ofsaturation and lightness. Error bars denote SEM ofthe mean.
Based on the significant main effect of saturation,
we plotted the rating values of miniature faking
averaged over the 28 participants as a function ofsaturation (Fig. 3). It is evident that the miniature
faking effect was strengthened by manipulations ofhigher saturation. The rating values as a function ofcolor lightness were also plotted in Fig. 3.
C. Discussion
In Experiment 1, we manipulated the color
lightness and saturation of two bird’s-eye viewphotographs, which were recreated as tilt-shift
photographs. The role of saturation was clarified by asignificant main effect revealed from ANOVA.
However, the function of color lightness remained
unclear because as shown in Fig. 3, the rated miniature
faking effect seemed to be similar among different
lightness conditions. One possible reason is that
Experiment 1 was conducted by using stimuli printed
on paper (surface color) while the color lightness ofstimuli was adjusted by using a computer display(luminous color). Another possible reason was thesmall sample in Experiment 1. Consequently, weconducted an online survey in Experiment 2; all thestimuli were presented through display devices andmore participants were recruited.
III.

EXPERIMENT 2

A. Methods
1) Participants
The participants included 250 people who wererecruited online through Yahoo! Crowdsourcing. Of

these, 237 participants (155 males and 82 females; 12–68 years old, mean ± SD age: 43.4 ± 10.1 years)
completed the experiment. The purpose of theexperiment was not revealed to the participants
beforehand.
2) Stimuli
We used the same 24 images, which were employedin Experiment 1, as stimuli. However, considering theuniversality of an online experiment, the resolution of
the images was compressed to 1000*750 pixels. Theimage processing was conducted by using a desktop
computer (iMac Pro, Apple, California) with Adobe
Photoshop CC 2019. The manipulations of saturationand color lightness were those used in Experiment 1.
3) Procedure
The script for Experiment 2 was created by using
jsPsych [8] and then uploaded to an online survey
website operated by us. Participants recruited fromYahoo! Crowdsourcing were guided to access ourwebsite to participate in the experiment.
After obtaining informed consent and collecting
demographic data, the experiment started with fivepractice trails in which stimuli were randomly selectedfrom the 24 images. The same method of rating withthe exception of rating values being changed from 1–7
to 0–6 was employed. The value, 0 meant no miniature
faking effect. In addition, rating scales were replacedby buttons with numbers to accommodate thoseparticipants who used tablets and smartphones. Afterthe practice trails, each of the 24 stimuli was tested
randomly without repetition. No time limits wereimposed for either the observation or response periods.
Some additional information was provided after theexperiment trials to help the participants obtain rewards
via Yahoo! Crowdsourcing.
B. Results
In accordance with Experiment 1, a three-way
within-participant ANOVA was conducted on themean rated values of the miniature faking effect withthe factors, stimulus, saturation, and lightness. In
accordance with the results of Experiment 1, the main
effect of saturation [F(3, 708) = 91.872, p < 0.0001],
and the interaction between saturation and lightness[F(6, 1416) = 2.192, p < 0.05] were revealed to besignificant. In addition, the main effects of stimulus[F(1, 236) = 19.908, p < 0.0001] and lightness [F(2,472) = 8.775, p < 0.001] were also significant. However,
the interaction between stimulus and saturation [F(3,708) = 0.522, p = 0.668], the interaction between
stimulus and lightness [F(2, 472) = 1.854, p = 0.158],
and the interaction among the three factors [F(6, 1416)= 1.442, p = 0.195] were not significant. Tests of simple
main effects on the significant interaction between
saturation and lightness demonstrated that the effect ofsaturation was significant for all the lightness
conditions [Original: F(3, 2124) = 50.549, p < 0.0001;+50 lightness: F(3, 2124) = 44.027, p < 0.0001; -50
lightness: F(3, 2124) = 55.292, p < 0.0001]. However,
the effect of lightness was significant only when thesaturation was original or enhanced [Original: F(2,1888) = 10.261, p < 0.0001; +50 saturation: F(2, 1888)= 4.200, p < 0.05; -50 saturation: F(2, 1888) = 0.150, p= 0.861; -100 saturation: F(2, 1888) = 2.876, p = 0.057].

The tests of simple main effects revealed the same
results of those in Experiment 1 with the exception of asignificant main effect of lightness with conditions oforiginal saturation.
Multiple comparisons were conducted by using
Ryan’s method [7]. With reference to the significant
main effect of saturation, there were significant
differences between +50 saturation and the original,
between +50 and -50 saturations, between +50 and 100 saturations (ps < 0.0001), which were alsosignificant in Experiment 1, between the original and 100 saturations, and between the original and -50
saturations (ps < 0.001), which were revealed
significant in Experiment 2 for the first time. In relation
to the significant main effect of lightness, there weresignificant differences between the original and +50
lightness (p < 0.0001), and between +50 and -50
lightness (p < 0.01). With regard to the significant
interaction between saturation and lightness, whenlightness was original or diminished (-50), differences
between all pairs of saturation conditions with theexception of -50 and -100 saturations were significant(ps < 0.01). When lightness was enhanced (+50),
differences between all pairs of saturation conditions
except for the original and -50 saturations weresignificant (ps < 0.01). When the saturation wasoriginal or enhanced (+50), differences between theoriginal and +50 lightness (ps < 0.05), and between +50
and -50 lightness (ps < 0.01) were significant.

Figure 4. Results of Experiment 2. The mean rated
miniature faking effects are shown as functions ofsaturation and lightness. Error bars denote SEM ofthe mean.
Based on the significant main effects of saturationand lightness, we plotted the rating values of miniature
faking averaged over the 237 participants as functionsof saturation and lightness (Fig. 4). Results revealed
that the miniature faking effect changed systematicallywith alterations of saturation and lightness.
C. Discussion
In Experiment 2, all the significant results inExperiment 1 were replicated. However, some new
findings were revealed. It was demonstrated that theminiature faking effect depended on the saturation.

Higher saturations induced a more enhanced miniature
faking effect. The new finding was related to therelationship between lightness and the miniature
faking effect. The results of Experiment 2 showed asignificant decrease of the miniature faking effect ininverse proportion to the color lightness of the stimuli.
The different roles of saturation and lightness arefurther explored in the general discussion.
IV. GENERAL DISCUSSION
In the present study, we conducted two experiments
to examine the roles of lightness and saturation in
inducing the perception of miniature faking. The
functions of the two color attributes were bothdemonstrated by the experiments with a significant
interaction with each other. The effect of saturation
concurred with the findings of previous studies thatgarish colors yielded stronger miniature faking effects[4, 5, 6]. We are of the view that these results are linked
with the finding that color saturation increases
perceived object size [9] because the perception thereof
leads to a reduction of observation distance, which ispossible only when people view things in miniature ordioramas. However, further investigations are needed
to examine whether the miniature faking effect occurs
with the objects, or the entire landscape or environment
in the photographs. In contrast to saturation, color
lightness was shown to correlate inversely with theminiature faking effect. This new finding is supportedby the fact that vignetting adjustment is anindispensable processing aspect when an ordinary
photograph is recreated to become a miniature-like one.
A previous study also found that darker photographs
produced stronger miniature images when observed
informally [4].
Although the influence of saturation and lightness
on the miniature faking effect has been revealed in thepresent study, psychophysical investigations with more
precise manipulations on color attributes as well asexperiments conducted in a laboratory withcontrollable lighting environment are imperative infuture investigations. Neurophysiological mechanismsof color perception and the miniature faking effectshould also be explored.
ACKNOWLEDGMENT
The present study was supported in part by theHirose Research Grant from the Hirose International
Scholarship Foundation, and by JSPS KAKENHI
Grant Number JP16K04427. We thank Mr. Miyaji andMr. Ueeda for providing photographs which were usedas stimuli.
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