Industrial
DESIGN
QUALITY PERCEPTION STUDY IN
SUSTAINABLE MATERIALS
IRENE RAMOS LAPESA
Master in Product Development with a specialization
INDUSTRIAL DESIGN
SUSTAINABLE MATERIALS
PERSEPTION AV KVALITETSSTUDIER I HÅLLBAR
MATERIAL
Irene Ramos Lapesa
This degree project is performed at the School of Engineering in Jönköping in the subject field Industrial Design. The project is a result of the master program Industrial
Design. The writers are responsible of the result, conclusions and reflections.
Tutor: Lars Eriksson and Linda Lundeholm Examiner: Lars Eriksson
Extent: 30 points (D-level) Date: 24/05/2021
Abstract
Abstract
The growing demand in the industry towards sustainability and the globalization of manufacturing lead to an industrial climate of constant development and improvements, and automotive interior design is not excluded.
In 2017 the European Union declared that the material used to generate the bright chrome surfaces of car interiors (CR VI) is toxic and carcinogenic.
This implies that Volvo will ban the use of Chrome VI for decorative parts from September 2024.
Finding a more eco-friendly alternative to replace CR VI not only functionally but also in terms of perceived quality and user experience will be an urgent and decisive action. In this project, the parameters of gloss, haze, color temperature, and metallic depth are investigated in order to figure out which elements ensure the perceived quality of chrome surfaces.
For this purpose, a user study based on different sensory tests and soft metrology was carried out with 48 people, as well as seven samples, five of them more eco-friendly alternatives.
This project aims to introduce a set of tools to assess and guarantee the perception of quality by supporting the development of "chrome-look" surfaces in the automotive interior with new sustainable materials.
Through this study, correlating soft and hard metrology, it is observed what makes a surface perceived as "high-quality" and which of the more eco-friendly alternatives could be the most optimal to replace Chrome VI in Volvo's car interiors.
Keywords
Affective engineering, Kansei engineering, User experience, User study, Quality perception, Customer appreciations, Sensory evaluation, Neuroaesthetic, Car interior design, Sustainable materials, Chrome surface, Chrome appearance, Chrome Plating, Hexavalent chromium,, Soft metrology, Material experience, Material meanings, Visual appearance.
Sammanfattning
Industrins växande krav på hållbarhet och globaliseringen av tillverkningen leder till ett industriellt klimat med ständig utveckling och förbättring, och inredningsdesign för bilar är inte undantaget.
År 2017 förklarade Europeiska unionen att det material som används för att generera de ljusa kromytorna i bilinredningar (CR VI) är giftigt och cancerframkallande.
Detta innebär att Volvo kommer att förbjuda användningen av krom VI för dekorativa delar från och med september 2024.
Att hitta ett hållbart alternativ för att ersätta CR VI, inte bara funktionellt utan även när det gäller upplevd kvalitet och användarupplevelse, kommer att vara en brådskande och avgörande åtgärd.
I det här projektet undersöks parametrarna glans, dis, färgtemperatur och metalliskt djup för att ta reda på vilka element som säkerställer den upplevda kvaliteten på kromytor. För detta ändamål genomfördes en användarstudie baserad på olika sensoriska tester och “soft metrology” med 48 personer, samt sju prover, varav fem hållbara alternativ.
Syftet med projektet är att införa en uppsättning verktyg för att mäta kvalitetsupplevelsen genom att stödja utvecklingen av ytor med "krom-look" i fordonsinteriören med nya hållbara material.
Genom denna studie, kombinerad med hård metrologi, observeras vad som gör att en yta uppfattas som "högkvalitativ" och vilka av de hållbara alternativen som skulle kunna vara de mest optimala för att ersätta Krom VI i Volvos bilinteriörer.
Table of Contents
Table of Contents
Abstract 2 Sammanfattning 3 Table of Contents 4 Introduction 6 Background 6Purpose and research question 7
Delimitations 8 Disposition 8 Theoretical Background 9 Industrial Design 9 Human-Centered Design 9 Design Process 10
Design thinking and doing 11 Product Experience 11 Perceptual Product Experience 12 Perceived Quality 13 Material Experience & Meanings 13 Material/Surface Masters 14 Chrome VI 15 Electroplating Process 15 Plating on plastic 15 Bright Chrome 15 Satin 16 Hexavalent chromium 17 Problems with hexavalent chrome 17 Alternative processes 17 PVD Technology 17
3-Layer coating 18 Copper Plating 19 Principle of Visual Appearance Measurement Methods 20 Geometric Attributes of Appearance 20 Physics of Color Attributes 21
Method 22
Design Brief 22
Double diamond 22
Gantt chart 23
Ideation and sketching 24
Mood Board 25
Word Cloud Visualization 25 Unstructured Interviews 25
Questionnaire 26
Soft metrology 26
Kansei Engineering 27 Sensory Evaluation 29 User Experience Methods 29 Discriminatory Analysis 29 Descriptive Analysis 29 Affective Analysis 29
Hard metrology 30
Theoretical Measurement of surfaces 30 Farnsworth Munsell 100 Hue Test 31
CIELab 32
Approach and Implementation 33
Discover 33
Material Research 33 Sensation and Perception Research 34
Table of Contents
Test methods Research 34
Define 35 Design Brief 35 Gantt Chart 36 Develop 36 Perception Lab 36 Panel setting 37 Samples collection 37 User Study Protocol 38 Introduction and context 38 Color calibration 39 Affective test 39 Descriptive test 40 Discrimination test 41 Semantic Scales Test 42
Deliver 44 Result 45 Soft Metrology 45 Population 45 Affective Test 47 Descriptive Test 52 Discrimination Test 58 Semantic Scales Test 60 Hard Metrology correlation 64 Conclusion and discussion 70
Conclusions about the method 70
Findings 71
Population 71
Descriptive Test 73 Discrimination Test: 74 Semantic Scales Test 75 Hard Metrology correlation 76 Final conclusions and future direction 77
References 79
Introduction
1 Introduction
This work is a thesis project within industrial design and product development at Jönköping University, carried out in collaboration with Volvo Cars during spring 2021.
1.1 Background
Metal parts and metal surfaces have been extensively in use for automotive interiors since the early days of motorism but during the last decades, environmental demands on decreased fuel consumption and environmentally greener and safer manufacturing processes have led to increased use of lighter and less carbon footprint plastic interior parts with plated or painted metal surfaces.
Since September 2017, European Union legislation has been increasingly strict with the use of the chemical compound chromium VI as it is dangerous and harmful to the environment and people. (See Appendix 3)
Volvo fully supports this European legislation and has set the highest standards not only for safety but also for sustainability.
This implies that Volvo will ban the use of Chrome VI for decorative parts from September 2024. (See Appendix 3)
Therefore, there is really an urgency to find more environmentally friendly alternatives to Chromium VI and this step towards sustainability will be decisive.
The metal plating products are manufactured by injection molding and plating and material variables influence significantly the appearance output. The manufacturing processes for generating those highly complex surfaces are therefore decisive in terms of the technical as well as the economic performance of the product.
The functionalization of surfaces is an important step for bringing special properties onto technical products.
Typical features are glossy metal surfaces for car interiors where gloss, color, and texture patterns heavily influence the total appearance. [35]
The current trends and developments lead to the introduction of new more- or less tested concepts of “shiny” interior parts, based on new materials and processes simultaneously as the customer in many cases and market segments demand higher perceived quality. The higher quality is not only expressed in terms of glossiness and color of chrome- or
chrome-looks interior parts but also of the visual variation and balance between nearby-or associated parts in the interinearby-or. [36]
Controllable injection molding- and coating processes result in predictable gloss and color levels but need to be completed with a matching quality system ensuring the glossiness and color over time and that surfaces are perceived as the “right” and expected quality by the end-user, -the customer. [35]
1.2 Purpose and research question
This thesis is part of an ongoing research project (2017) involving Volvo Cars, Jonkoping University, and various plastic manufacturers.
The project aims to develop an integrated and standardized quality system that guarantees a visual similarity and perceived quality of the chrome surfaces for the interior design of vehicles replacing the hexavalent chrome to be an environmentally friendlier alternative but still be perceived as a high-quality surface just like the Cr VI.
The objective of this thesis is to determine which more eco-friendly alternative is the most similar to Chrome VI in terms of perceived quality.
For this, it is intended to design a user study protocol based on different sensory tests where users analyze specific parameters of the surfaces such as: haze, gloss, color temperature and metallic depth.
The problem question is then divided into a main question and a secondary question. Each one of the questions has been divided into more specific sub-questions to guide the study and the results obtained.
Main question:
● Since Chrome VI is toxic, which more eco-friendly alternative is the most optimal in terms of user experience and perceived quality to replace Chrome VI?
■ Which sample is the most similar to the A-master? ■ Which sample is the most preferable?
■ Is the most preferable the most similar to the A-master as well?
Secondary question:
● What standards and specifications are needed to ensure the perceived quality of chromium coated pieces?
Introduction
■ What characteristics of the surfaces cause a sample to be perceived as better quality and therefore more preferred?
■ Does the perceived quality depend on the background and/or the trained eye of the user?
■ Is there a correlation between the different surface parameters (metallic depth, color, gloss...)?
1.3 Delimitations
The thesis project refers to the development of a study on how the appearance of a more eco-friendly material can affect the user's perception of quality.
The delimitations are mainly:
● Due to the current pandemic situation tests will be held with a limited number of people and with proper precautions.
● The sample of more eco-friendly materials obtained by the manufacturers, among them, Chrome VI, Chrome II and PVD film. The results of the study could vary depending on the chosen more eco-friendly alternative samples. (See Chapter 4.3.3)
● The perception results from the user study are based on test conditions and not car interior. That means the perception of the new material could vary because of the context. The distance between the different pieces and the materials next to the piece could change the perception effects when this new material would be placed in a real interior car. [27]
● Hard metrology is not part of the study although it has been taken into account in a basic way to correlate it to soft metrology in order to draw relevant conclusions.
1.4 Disposition
The background and theoretical background are intended to create an understanding of the work area.
The project focuses on Soft metrology and its effectiveness in determining which materials are best suited to achieve a perception of quality. Consequently, a series of methods and implementations are followed to describe and define the chosen approach. Finally, the result is presented, from which a series of conclusions are drawn.
2 Theoretical Background
2.1 Industrial Design
In the book “The design of everyday things”, Donald Norman describes industrial design in this way: “The professional service of creating and developing concepts and
specifications that optimize the function, value and appearance of products and systems for the mutual benefit of both user and manufacturer” (Norman, 2013).
Design shows how objects work, how they are controlled, and how the interaction between people and technology takes place. [2]
2.2 Human-Centered Design
Human-centered design is a method that can be applied to both industrial design and experience design or interaction design.
Human-centered design focuses on meeting user needs by tailoring the design to those needs. This is done through an understanding of psychology and technology
communicated to the user. It is through observations of human behavior related to the product that understanding of these needs is achieved. [2]
Industrial design in combination with the human-centered design philosophy aims to identify the correct problem to solve it satisfying the user's needs by finding the right solution. It is about creating a pleasant interaction with the object.
This interaction experience consists of six fundamental concepts, according to Norman (2013):
● Affordance: Those perceptible characteristics of the object that give it an intuitive aspect when it comes to knowing how to use it
● Signifier: A tool that communicates objective, structure and performance through marks or sounds. They are intentional or unintentional clues, which direct and give meaning to those who are interacting.
● Constraint: It is a limit that can be physical, semantic or cultural that delimits an action or simplifies the way of interpreting it.
● Mapping: In “The design of everyday things” mapping is described as “the relationship between the elements of two sets of things”.[2]
● Feedback: the response that a receiver transmits to the sender, based on the message received, this being a two-way communication.
● Conceptual model: It refers to the operating mode and how the user interprets that object or how to use it.
Theoretical Background
2.3 Design Process
Over-the-wall design method
Traditional methods (Arts and Crafts, mastership....) in which only one person could design and manufacture a complete product changed due to the increasing complexity of products in the mid-20th century.
The design process evolved into "over-the-wall design", where the work is divided into different groups that are responsible for the different parts of the process. In this way, the workflow is fast and linear when using one-way communication.
This method is a popular sequential method today but it has some flaws. The fact that the information is only transmitted in one direction generates a limited contact between the groups and therefore a less understanding of the design problem, which can generate a solution that is not the expected one.
The over-the-wall process is in “The mechanical design process” described as an inefficient and costly process that many companies are now moving away from.[3]
Integrated product and process design (IPPD)
In the early 1980s, the design process became a simultaneous process. In the 1990s, it became an integrated product and process design.
The objective was to promote teamwork and continuous communication between groups to avoid wasting information.
As all stakeholders are part of the process, understanding the problem is simplified. The objective of the IPPD is “on the integration of teams of people, design tools and techniques, and information about the product and the processes used to develop and manufacture it” (Norman, 2013).
Design with a human-centered approach is based on four methods; observation, idea generation, prototyping, and testing iterated until a satisfying solution is found. [2]
2.4 Design thinking and doing
Traditional way of solving problems is to first establish the problem or need to be solved, then plan a strategy and then generate ideas and evaluate them. Finally, the most suitable solutions are selected. [3]
Design thinking is a tool made up of creative methods that the designer can apply to a problem, setting a goal.
Design Thinking is based on the investigation of the known and the unknown for possible solutions with a clear objective.
This process is an iterative process, this means that each phase can be repeated as many times as necessary or go back to repeat a phase. [4]
David Kelley, founder of IDEO, describes design thinking as “the intersection between what the people want and what can be achieved, both technically and financially”.[5] Design doing is by IDEO described as a way of designing through trial and error, developing ideas that can quickly be subtracted and evaluated.[5]
2.5 Product Experience
Experience is an intangible phenomenon that can have three different characters: aesthetic experience, the experience of meaning, and emotional experience. [10]
● The aesthetic experience refers to how we perceive the product through our senses.
● The experience of meaning refers to the characteristics that we attribute to the object.
● Emotional experience refers to the emotions we experience due to the product. All these experiences can happen at the same time and generate a complete experience. [11]
Theoretical Background
2.6 Perceptual Product Experience
The Perceptual Product Experience framework is a model for analyzing and understanding different types of user experiences.
There are three types of user-product interactions: sensory, cognitive, and affective. PPE focuses on how we interact with products on a sensory level, how we process stimuli, categorize them and make sense of things, and finally, how we feel and what we think when we experience products. [19]
Figure 2. Framework of perceptual product experience(PPE), with core modes(center) and the two dimensions of presentation (left) and representation (right) with submodules. [19]
2.7 Perceived Quality
Perceived quality has been associated with different concepts throughout history,
however, today we could say that it is the antagonism of objective or real quality, that is, subjective quality. [41]
"The perceived ability of a product to provide satisfaction concerning available alternatives" (Monroe and Krishnan, 1985).
It is this subjective character that makes it difficult to determine what perceived quality is, since it depends on the individual who perceives it as well as the context and other
elements with which it is compared. [41]
Because of this, a framework has been proposed to develop a more precise definition. [41] This framework is made up of three dimensions of value:quality perceived as preference, perceived quality that is neither objective or subjective, and perceived quality that exists in the consumption of the product. [41]
Studies have been conducted on aesthetics and visual quality in the automotive industry. However, the visual quality is not limited only to the visual appearance but it is a series of factors that are perceived through all the senses when there is an interaction with the material. (Figure 3) [41]
2.8 Material Experience & Meanings
Material experiences are closely related to product experiences since products have materials that will be unconsciously interpreted and that will generate a specific emotion or reaction in the user.
The product itself does not generate an emotional response, but rather the interpretation of the product by the user.
Material experiences are divided into three types: aesthetic experience, the experience of meaning, and emotional experience. [10]
Materials have certain meanings.
Materials can have different meanings than products since material and product are not the same.
These meanings are due to our previous and acquired experience when interacting with the materials that surround us. The meanings of the materials are determined by the context.
Theoretical Background
For example, normally wood is attributed to the natural while plastic is attributed to the artificial. [10]
To convey the proper meaning, designers must understand how this material-form relationship works and the variables that play in the process of material meanings.
An example is how people associate metal with sharp edges and plastic to rounded edges or organic shapes. This is due to the limitations of the manufacturing processes that are different for these two different materials. [12]
Another influencing factor is context and culture. Depending on the origin of the person it will have some learned meanings. For example, in Scandinavia stone houses are
considered more luxurious than in the Mediterranean, where the opposite happens. [12]
2.9 Material/Surface Masters
The quality evaluation of a material is determined by a standard that must be met so that all parts generated have quality and a mandatory similarity.
This evaluation is done by making a comparison with a material sample.
Volvo uses some different kinds of Masters. They are named in the following way “A-Master”, “G-Master”, “B-Master”, “CD-Master”, “P-Master”.
This is Volvo's definition of the masters.
• A-Master is the first master and is usually the visual request from the design department of how a surface should look like.
• G-Master is the grain master for materials that have a grain (grain is a texture on the surface of the material).
• B-Master is the master when technical demands for the surface should be met, for example, scratch resistance.
• CD-Master is when the color and gloss are set. • P-Master when it is ok for purchasing. [14]
2.10 Chrome VI
2.10.1 Electroplating Process
Electroplating is a manufacturing process in which a thin layer of metal is added to a surface of an electrically conductive material.
The process consists of immersing the material in a fluid with metal dissolved in it. The electric current causes the material to become negatively charged while the metal ions in the fluid become positively charged causing both to attract each other, in this way the material is coated. [24]
2.10.2 Plating on plastic
Plastic coating (POP) is a process of coating plastic parts with metals.
The purpose of this coating can be decorative or functional, depending on the thickness of the deposition.
Decorative tanks are typically less than 0.80 μm thick and give a nice chrome appearance while offering resistance to corrosion.
Chromium functional deposits are typically greater than 0.80 μm thick and are used for industrial applications.
Since plastics are not conductive, it is a more complicated process than electroplating. The process is divided into five steps: etching, etching neutralization, catalyst application, catalyst activation, and plating. Before the process begins, the plastic parts need to be cleaned for the plating to work best. [25]
2.10.3 Bright Chrome
Bright chrome finish (Figure 4.1) is normally classified as commercial chrome and is not polished.
It is the electroplating process that is the same for both bright and polished chrome. The only difference between the two is the way the materials are handled. For example, most objects are nickel-plated before commercial chrome plating. [26]
Theoretical Background
Figure 4.1. High-gloss Chrome VI, sample G.
2.10.4 Satin
Satin chrome or matt chrome is a finish that has been used for many years as both an industrial and decorative finish.
Before electroplating, the object is first passed through a mechanical staining operation. It is in this step where the texture and gloss of the finish develop according to the medium used during staining. Once stained, that's when it enters the electroplating operation. Satin chrome is typically plated with a nickel coating before chrome plating to achieve a uniform finish and better performance. [26]
However, satin chrome can also be achieved directly without any mechanical operation, simply with a satin nickel base coat.
Figure 4.2. Satin Silk Chrome VI, sample A.
Shown in this image (Figure 4.2) is a satin finished chrome part that gives it a bluish white color and provides a gloss finish coat appearance.
2.10.5 Hexavalent chromium
Hexavalent chrome or hexagonal chrome, Cr + 6, and chrome (VI) are characterized by chromium trioxide (also known as chromic anhydride) which is its main ingredient. The hexavalent chrome is normally used for decoration.
The typical hexavalent chrome plating process is divided into the following steps: activation bath, chrome bath, and rinsing. The activation bath typically consists of a
chromic acid tank with a reverse current running through it. This etches the surface of the workpiece and removes any scale.
In some cases, the activation step is done in the chrome bath. The temperature and current density in the bath affect the final gloss and coverage. Finally, the entire bath is agitated to keep the temperature stable and achieve a uniform deposition. [26]
2.10.6 Problems with hexavalent chrome
A disadvantage of hexavalent chrome plating is the low efficiency of the cathode, which generates a coating that is not sufficiently uniform, with more in the corners and less in the interior area.
In terms of health, it is the most toxic form of chromium.The EPA (Environmental Protection Agency) defines chromium as a dangerous air pollutant and also a carcinogen. According to the Clean Water Act, it is a priority pollutant.
According to the law of conservation and recovery of resources it is a dangerous component.
The reasons for these considerations are due to the release of toxic water vapor due to its low cathodic efficiency and high viscosity. [26]
2.11 Alternative processes
2.11.1 PVD Technology
PVD is based on thermal evaporation that is performed in a high vacuum environment where the temperature is raised to bring the coating material to its boiling point. This causes a vapor stream to enter the vacuum chamber where the material is transported in the vacuum and lands on the substrate due to its polarity. (See Appendix 3)
Theoretical Background
Figure 5. PVD process (See Appendix 3)
Apparently this method has better environmental performance than Cr VI: in terms of global warming is 40 times better and in terms of resource depletion is 146 times better. (See Appendix 3)
Figure 6. Environmental benefits of PVD process (SeeAppendix 3)
2.11.2 3-Layer coating
3-Layer coating is a coating process which consists of covering the substrate with three layers. The first layer is a colored primer, the second layer is the base coat and the third layer is the topcoat with the final finish. (See Appendix 2)
Figure 7. 3-Layers coating process (See Appendix 2)
This coating process is intended to replace the traditional chrome coating process and has the following advantages: (See Appendix 2)
● It mimics chrome and could be a substitute. ● More environmentally friendly technology ● Greater variety of color
● Variety of applications ● High resistance
● Laser engravable ● Printable
2.11.3 Copper Plating
Copper plating is a process in which a layer of copper is electrolytically applied to a plastic part to obtain a finish.
The process consists of dissolving a copper rod and transporting the ions to the part. For this phenomenon to occur, it must be done in an electrolytic cell where electrolysis takes place by placing the part (cathode) and the copper (anode) in a container with water. This process generates a thin, solid copper film on the surface of the part. [37]
Theoretical Background
2.12 Principle of Visual Appearance Measurement
Methods
The reflection and transmission of light are what determines the visual appearance of an object.
On the one hand, color is produced by wavelengths that are reflected or transmitted without being absorbed.
On the other hand, brightness or opacity is due to the directional distribution of reflected or transmitted light. [1]
The appearance of an object is determined by human perception and the visual characteristics of the object and the reflection of light.
The perceived quality with respect to appearance is psychologically related to the expected performance and lifetime of the object.
Appearance is composed of all visual phenomena such as color, brightness, shape, texture, gloss, haze and translucency that characterize objects. [1]
Although the appearance of the surface of the material, including the printed ones, is the result of very complex factors, the problem can be simplified for analysis by separating the chromatic attributes such as color, gloss, haze, and separating the diffuse light distributions of the speculate.
The measurable attributes of the object's appearance are divided into two groups: geometric attributes and color attributes. [1]
2.12.1 Geometric Attributes of Appearance
Geometric appearance attributes are those associated with surface properties, not necessarily just color.
By considering relatively flat and uniform surface areas and diffuse and specular light distributions, it is possible to make some significant simplifications of geometric attributes. Since transmitted and reflected light can in turn be divided into two types of lights: diffuse reflection and specular reflection, this generates a total of four types of light distribution: diffuse reflection, specular reflection, diffuse transmission, and regular
transmission.
The physical analysis of the combined results of these processes is performed using a spectrophotometer and goniophotometer measurements. [1]
● Physics of Color Attributes
Color is associated with light waves, specifically, their wavelength distributions, also known as spectrophotometric characteristics. Selective absorption of different amounts of wavelengths determines the colors of objects.The goniophotometer measures the scattering of light as a function of different lighting angles. Physically, the color of an object is measured and represented by spectrophotometric curves, which are graphs of fractions of incident light asa function of wavelength
throughout the visible spectrum relative to a reference. [1]
● Reflexion (Gloss and Haze): There are occasions when the beam of light striking a surface is scattered and does not coincide with the specular direction. The power of the incident beam is divided among all the reflected beams. Peak power is reflected in the specular direction. [25]
The high-quality surface is characterized by having a clear and shiny appearance. (Gloss)
Microstructures on the surface that generate poor dispersion cause a milky appearance. (Haze)
This phenomenon is called milkiness or haze. It is a high gloss surface but with a particular texture that causes diffuse light with low intensity adjacent to the main direction of reflection. Much of the incident lightis reflected in the specular direction causing a shiny surface that can even reflect images. But when not all the incident light is reflected, a milky haze appears. [25]
Method
3 Method
3.1 Design Brief
Design brief is the first step in a design project which consists of a description of the project with the objectives of the project and the framework or context on which you are going to work. This writing helps to achieve the desired results without
misunderstandings. [15]
The brief can be verbal or written but preferably written. [16]
The design summary is structured and adapted to the needs and characteristics of the project.
3.2 Double diamond
To develop the whole project, the methodology followed is based on the Double Diamond model. [8]
The Double Diamond was developed by the British Design Council in 2005. The Double Diamond model is a system that designers can follow, and was the result of a study involving giants like Microsoft, Starbucks, Sony, and LEGO.
The Design Council was required to learn more about how people process knowledge to create solutions, and they were surprised to find that across corporations, people followed the same steps for innovation. Each company had its name for this process, each
company did it in a particular way, but they all went through these stages whenever they faced a problem, a challenging task or an opportunity. [8]
Figure 10.Double Diamond Diagram [8]
It is based in four phases:
● Discover: The first diamond helps people to understand, rather than just assume, what the problem is. It involves talking and spending time with people affected by problems.
● Define: The data obtained from the discovery phase can help you to define the challenge differently.
● Develop: The second diamond encourages people to give different answers to the defined problem, seeking inspiration elsewhere and co-designing with a variety of different people.
● Deliver: Delivery involves trying different small-scale solutions, rejecting the ones that won't work, and promoting the ones that will.
It is important to remark that this model is not linear in any way. In fact, people are encouraged to come and go between these stages to fully understand what the problem is and how they can solve it or develop an existing solution. [8]
3.3 Gantt chart
The Gantt chart is a tool for planning and scheduling tasks over a specified period. Thanks to a simple and comfortable visualization of the planned actions, it allows to monitor and control the progress of each of the stagesof a project and, in addition, graphically reproduces the tasks, their duration, and sequence, to the general project calendar. [9]
Method
Developed by Henry Laurence Gantt at the beginning of the 20th century, the diagram is shown in a horizontal bar graph ordered by activities to be carried out in specific time sequences. [9]
The actions to each other are linked by their position in the schedule. The start of a task that depends on the achievement of a previous action will be represented with a link of the end-start type.
The steps to follow are:
1) The first step in creating a Gantt chart is to make a list of all the activities that a project may need. It should define the times for the completion of each task, priorities, and order of achievement. In addition, is it important to group the activities by specific items to simplify the graph as much as possible.
2) The design of the Gantt chart should be as schematic as possible. It should convey the most important things, as it will be consulted frequently. The people involved in the process should have a clear idea of what is happening at a specific moment in the process. 3) If desired, a more detailed version can be created and kept up to date for the person executing the project. Thanks to the Gantt chart, clear progress monitoring is possible to easily discover critical points, periods of inactivity and to calculate execution delays. 4) Finally, it should be said that due to its simplicity, ease of use and low cost, it is used very often in small and medium-sized companies and design departments.
3.4 Ideation and sketching
The sketch, being a type of drawing, obtains certain characteristics of this representation. From a material point of view it takes operational means; from the conceptual, the
construction of a static image. Finally, the construction techniques use perspective to generate the illusion of space: volumetry and isometry. These traditional techniques are still valid and key when addressing freehand representation, particularly in the description of objects through projections.
The sketch is the way of formal representation that assists the first synthesis of solutions. It forms a highly creative stage where the interface is able to adapt to the speed of the mental process to externalize, register and explore possible solutions. [13]
3.5 Mood Board
A mood board is a collage of images that express a feeling, theme, or values of a target group. The mood board is used as a source of inspiration and guide during the ideation. [28]
3.6 Word Cloud Visualization
A word cloud visualization is a method of displaying keywords or tags in an area where they can be classified in different ways, for example by alphabetical classification, although the most common is relevance classification. [30]
Figure 11. Word cloud visualization of all seven "HarryPotter" novels. [30]
3.7 Unstructured Interviews
An unstructured interview is a type of flexible interview where the answers of the users allow generating new questions. This means that there is no list to follow, but the
interview flows and adapts to the user's responses. This technique is used to collect extensive data from a target group and allows a deeper understanding of the motivations and beliefs of users and their reasoning.
Unstructured interviews differ from unstructured interviews in that they provide relevant opportunities to follow up on interesting leads. [17]
Method
3.8 Questionnaire
It is a technique that consists of collecting information through a series of questions that are asked to a group of people individually or in a group. The goal is to get a lot of information in a short time. [18]
3.9 Soft metrology
Soft metrology is a set of measurement techniques and models whose objective is to objectively quantify the sensations perceived by the sense organs.
Soft metrology consists of the measurement of physicalparameters and the construction of a model where these parameters are correlated with the variables that need to be quantified. [22]
Organizations must understand the needs of their current and future customers. Each interaction with users provides an opportunity for improvement and the creation of greater value.
The potential of soft metrology lies in the correlation between subjective perception and objective properties. The objective is to define the appropriate research methods to answer the question: "How do you feel about it?" [29]
This type of method requires an interdisciplinary approach where different theories and scientific methods based on physics, biology, sociology and psychology are used.
Human-Centered Design is a design philosophy that is closely tied to soft metrology.
Figure 13. Word cloud of what soft metrology involves.[29]
3.9.1 Kansei Engineering
All products are not physical objects. There are products that can be physical objects and products that can be services, and also the combination of both. Even physical objects have an intangible characteristic since, in some way, they will always generate an
(intangible) experience. [7]
Kansei engineering attempts to discover the connections between the physical properties of an object and the user's experience and perceptions based on those properties.
Kansei Engineering originated in 1970 by Misuo Nagamachi in Japan. Mitsuo Nagamachi presented an affective product development method that he called "Emotional
Method
seen as a product evaluation method that takes consumer impressions, feelings, and demands on products or concepts and helps make new designs with a higher quality of user experience. [7]
For this thesis, the methodology has been adapted dividing the process into 6 phases. [6]
The 6 phases are:
• Pilot study: it is about defining the domain and its stakeholders.
• Describe the experience: collect words that are used when describing the domain (Kansei words).
• Define Key Product Properties - Collect the physical properties of the product that affect the user.
• Connect experience and product properties: using qualitative studies in focus groups or other methods.
• Validity checkpoint: Validation and analysis of collected data.
• Synthesis and Domain Modeling: Design and validation of a “prediction model”.
3.9.2 Sensory Evaluation
Sensory evaluation is a scientific discipline that measures, analyzes and interprets, through different methods, human responses to the properties of objects and materials perceived by the five senses: taste, smell, touch, sight, and hearing. [20]
There are five basic principles (5 S’s) that an applied sensory test should contain: 1. Subjects
2. Site 3. Statistics 4. Samples
5. Sensory methods
3.9.3 User Experience Methods
There is a classification of methods for the sensory evaluation test where three different types of sensory tests are described. [21]
● Discriminatory Analysis
The discriminatory analysis is an analytical test whose objective is to test the perceived similarity between two products or materials to verify how similar a new version is to the original.
● Descriptive Analysis
In the descriptive analysis, a semantic differential scale is used to categorize the intensity of the perceived attributes. In this analytical test, quantitative results are obtained and it requires trained users who have learned to identify different characteristics of the product with which they interact.
The goal of the analysis is to characterize the perceived feel of a product.
● Affective Analysis
The objective of the affective analysis is to identify which product is preferred by the user and how appreciated it is. In this analysis, it is necessary that the users have no previous knowledge.
Method
3.10 Hard metrology
Hard metrology is the science that studies the measurements of quantities, guaranteeing their normalization through traceability.
It consists of the study, maintenance, and application of different systems of weights and measurements using highly accurate instruments since the main objective is to obtain and express the value in magnitudes with the least error. [34]
Figure 15. Correlation between hard and soft metrology. [34]
3.10.1 Theoretical Measurement of surfaces
Today the texture of a surface is one of the mostimportant factors that determine the visual performance of an object.
The roughness of a surface is another determining factor.
Surface metrology ranges from the nature of the surface and its use to the practical aspects of measurement, so clarification of the useof the surface will be given as a prerequisite to measurement. There is no description of the parameters as such in what follows, but rather a justification for the measurement.
Height parameters:
● Sq, the root mean square height, represents the root mean square value of the peaks of the surface. z(x,y) within the area of definition,A. Equivalent to the standard deviation of the peaks.
● Sa, the arithmetic mean height, represents the arithmetic mean of the absolute value of the peaks within the area of definition.The parameters Sa and Sq can be used interchangeably because they represent the same thing, however Sq has more statistical significance.
● Ssk, skewness, represents the degree of steepness of the peaks. It is the ratio of the mean of the peak values to the cube of Square withina definition area.
Figure 16. Relation between Ssk values and shape peaks. [23]
● Sz, the maximum height, is the sum of the height of the highest peak (Sp) and the depth of the deepest hole (Sv). [23]
Statistics software (JMP): JMP is software created in 1989 by SAS (Statistical Analysis
System) to enable science and engineering professionals to visually analyze data. The way you view data is interactive through powerful statistics. [39]
3.11 Farnsworth Munsell 100 Hue Test
Farnsworth Munsell 100 Hue is a simple laboratory test to assess color vision and tone discrimination.
This test will determine how accurate the user is able to see color differences. The colored boxes at the ends are fixed.
The user has to classify the color boxes creating a coherent transition between the two extremes.
Method
A perfect score will be scored as 0 and means that the order of the colors is correct. [31]
Figure 17. Color rows of the Farnsworth Munsell 100Hue Test [31]
3.12 CIELab
The CIE L * a * b * (CIELAB) is the color model commonly used to describe all the colors that the human eye can perceive, developed for this purpose by the Commission Internationale d'Eclairage (International Commission on Illumination), which is why it is abbreviated CIE.
The Lab color model has been created to serve as a reference, independent of the device used.
The asterisks (*) that follow each letter are part of the name, as they represent L *, a *, and b *, from L, a, and b.
The three parameters in the model represent the color luminosity (L *, L * = 0 yields black and L * = 100 indicates white), its position between red and green (a *, negative values indicate green while positive values indicate red) and its position between yellow and blue (b *, negative values indicate blue and positive values indicate yellow).
The Lab color model is three-dimensional and can only be adequately represented in three-dimensional space. [32]
4
Approach and Implementation
This chapter explains the implementation of the methods and which ones have been selected, adapted, and implemented in the user study. The process to follow has been structured following the four phases of the double diamond: Discover, Define, Develop, Deliver. (See Chapter 3.2)
4.1 Discover
The first stage of the project consisted of a smallliterature study regarding sensation and perception research.
4.1.1 Material Research
In this phase, different chrome coating processes were investigated: Plating on plastic as well as more eco-friendly alternatives such us: copper plating, PVD and 3-layers coating. The inherent characteristics of surfaces and materials, the parameters like gloss, haze and color were also investigated and how materials affect user experience and have meanings for users.
Once a general study on materials and processes had been carried out, a deeper and more specific investigation was made regarding hexavalent chromium, which is the material to be replaced and the core of this project.
Both bright chrome and satin silk chrome were investigated, and the toxicity problems this material has for both people and the environment was discovered.
At this point the different parameters to evaluate and the type of chrome to use as an A-Master was discussed with Volvo R&D, and the research group.
This research served to better understand the object of study and its problems.
In this stage, all the necessary information was collected to understand the problems of chrome VI and the phenomena that occur on surfaces that affect the user experience, and therefore, the perceived quality.
Approach and Implementation
4.1.2 Sensation and Perception Research
Since we realized in the previous stage that materials and surface characteristics could influence the perceived quality, we decided to dedicate the next stage of the project to research user experience and perceived quality.
At this stage, the product experience and the perceptual experience of the product were investigated.
Information was collected on how the process works from sensation to perception and the elements of our body that are involved.
Now that we knew what Chrome VI was and understood how perceived quality was produced, it was time to investigate methods to develop our study that would be based on assessing more eco-friendly alternatives and Chrome VI and see if the perceived quality would be similar.
4.1.3 Test methods Research
The method research stage began by researching the popular Kansei Engineering technique.
Kansei Engineering is a Japanese method that allows identifying the values associated with the characteristics of a product to understand the user experience generated and therefore, to improve it.
This technique works with soft metrology.
For this reason, we decided to investigate what this double metrology consisted of. There are two types of metrology, the hard and the soft. Soft metrology is a set of measurement techniques to objectively quantify the sensations perceived by the sense organs. In this metrology, we work with people, subjective concepts, and sense organs.
However, hard metrology is a set of measurement techniques of the physical features of the surfaces. This metrology uses precise measurement tools and instruments.
Hard metrology could be useful to measure the gloss, haze, and color of surfaces and to identify the differences between different more eco-friendly alternatives and Chrome VI. On the other hand, soft metrology allows us to know people's feelings.
Correlating the results of soft metrology and hard metrology would make it possible to establish relationships between the physical characteristics of the samples and the quality perceived by the users. At this point the group research from Halmstad University agreed
on carrying out the hard metrology as well and this data would be collected by Jönköping University and would be used to support this study results. (See Chapter 3.10)
Finally, a more in-depth investigation was carried out on sensory evaluation based on literature review. (see Chapter 3.9)
This last part of the entire research phase was very fruitful since it allowed us to know the most appropriate methods on which to base the user study protocol.
4.2 Define
In the second phase of the project, we use the information collected in the previous phase to define how the user study would be carried out and what parameters will be evaluated.
4.2.1 Design Brief
Following the guidelines of what is known as a design brief, a framework was defined to work on when designing the user study protocol. (See Chapter 3.1)
In order to design and carry out the user study protocol we worked in collaboration with Volvo experts and Phd students from Halmstad University.
The objective of this project is to determine which more eco-friendly alternative is the most similar to Chrome VI in terms of perceived quality. For this, it is intended to design a user study protocol based on different sensory tests where users analyze specific
parameters of the surfaces. (Van Gool and Ramos Lapesa, 2021)
In collaboration with Volvo and the research group, it was decided to measure the
perceived appearance of haze, gloss, color temperature and metallic depth since these are the main geometric appearance attributes. (See Chapter 2.11)
The possibility of working in collaboration with the University of Halmstad and the research group where they would carry out the same study and also a hard metrology study was considered. In this way, we would obtain more complete results, and therefore, we would increase the possibilities of generating more relevant conclusions.
Approach and Implementation
4.2.2 Gantt Chart
Once the study framework was defined, a calendar was made in which the different phases of the project and their respective specific tasks were distributed on specific dates that would allow establishing global planning and meeting project deadlines. (See
Appendix 6)
4.3 Develop
4.3.1 Perception Lab
To carry out the user study, a room was equipped only for this purpose.
The room has white walls and does not have any external light source (pendant lamps or windows were turned off or covered). These features allow the light parameters to be controlled. (Van Gool and Ramos Lapesa, 2021)
Figure 19. Setup of the user study. Figure 20. Moodboard and sample population.
On the side of the room, a table and a chair were placed where each user would individually assess the samples.
A special lightbox (Figure 19) for this type of surface evaluation was placed on the table, identical to the ones used at Volvo:
Likewise, the light was configured with the same parameters used in Volvo: Daylight D65 as an illuminant, and 6500 K.
4.3.2 Panel setting
The number of users in the population for the study will be at least 15 per place. The user study was carried out in three different places with three different populations: Volvo experts, Halmstad University engineers and Jönköping University designers. It was
decided in that way to have more accurate results since probably the perception would be different based on the background and the train of the eye of the user.
The population will be a mixed age group between 18 and 50 years of mixed gender. This sample size was chosen in that way to obtain data from a sufficiently large and varied population for the results to be valuable. (Van Gool and Ramos Lapesa, 2021)
4.3.3 Samples collection
The samples have been provided from 4 different companies: POP, Plasman, Atotech, and AMB.
In total, we have 7 different samples, where two of which are Chrome VI (High-gloss and Satin Silk) and the remaining 5 are different, more eco-friendly alternatives.
Table 1. Samples data and code names.
Each sample has a letter assigned and a complex code that will be visible to users so that it is difficult for them to memorize or associate it during the study and does not affect their decisions. (Van Gool and Ramos Lapesa, 2021)
Approach and Implementation
4.3.4 User Study Protocol
The protocol went through Sensory Evaluation and Soft Metrology reviews from Volvo R&d, research group Halmstad & JU. After some iterations, a box with samples were sent to Volvo for their expert opinion/tests in order to get a conclusion regarding the
extremes of color as well as polish the final user study protocol.
The user study protocol is divided into 6 parts: introduction and context, color calibration, affective test, descriptive test, discriminative test, and semantic scale test. The order of the tests is important because it is progressive: the tasks in the tests go from more intuitive and emotional to more rational and conscious.
The affective test goes at the beginning because it is necessary that the users are not influenced for the result to be optimal. (Van Gool and Ramos Lapesa, 2021)
The descriptive test generates a more intuitive result. However, the descriptive test is performed in a more conscious way, so it should come later to be a confirmation of the previous test.
Figure 22. Index of the user study protocol.
● Introduction and context
At the beginning of the study, the user will be explained what it will consist of and what the objective of the study is. On the other hand, it will be shown a mood board from the interior of a Volvo car to familiarize with the context where the samples would be. In the first step of the user study we want to give the
participants the context of the placement of the chromepieces using a moodboard. It gives them the impression of the surrounding colors, distance between the parts and the chrome that is used in the interior. They will also get a short explanation of the user study and what they can expect. (See Chapter 3.5)
Figure 23. Mood board of a Volvo car interior.
● Color calibration
To verify that the user is able to differentiate between colors and does not have any vision problems such as color blindness, the Farnsworth Munsell 100 Hue Test will be carried out, where the user will also become familiar with the sorting of elements according to color and scales (methods to be used later in the study). (See Chapter 3.11)
In this way, his visual ability to differentiate colors will be known and the user will be trained to practice the following study steps. A perfect score of zero means the individual sorted all the colors in the good order. (Van Gool and Ramos Lapesa, 2021)
● Affective test
The objective of this test is to know the user's preferences without his perception being influenced yet. To carry out the affective test, a method called "maxdiff variation" has been used, where participants have to evaluate 10 different sets of three surfaces, randomly generated by software. The most appreciated sample is given a value of 1 and the least appreciated is given a value of -1, the remaining sample has a value of 0. [33]
While the test is being carried out, the user is asked to communicate aloud their thoughts regarding their decisions and their comments are noted. (see Chapter 3.7)
Approach and Implementation
Figure 24. Visual representation of the affectivetest.
● Descriptive test
The descriptive test is divided into two parts: the gloss evaluation and the color evaluation. To evaluate the gloss, the most glossy sample is placed at one end and the lowest gloss sample at the other end. In this way the user has the references of the ends. The user is then given the rest of the mixed samples and asked to order them on a scale from least glossy to most glossy. We proceed in the same way with the evaluation of the color, placing the most bluish at one end and the most yellowish at the other end. (Van Gool and Ramos Lapesa, 2021)
This method allows you to know which samples are the most similar to the A-master, which will be on both sides of it. It also allows you to compare the samples between them. This method is more intuitive, because they don’t compare directly with the A-master.
Figure 26. Visual representation of the gloss descriptivetest.
● Discrimination test
The objective of this test is to know exactly which sample is the most similar to the A-master in terms of color and gloss.
In this test, the user is revealed to be the A-master and given the ordered scale above, he is asked to place the A-master on that scale, aligning it with one of the samples. (Van Gool and Ramos Lapesa, 2021)
For this test, there are 6 samples in a line and 1 sample above the sample line, this is the reference. You will need to place the reference on top of the sample that is most similar in terms of brightness first, then color. This decision they make is more conscious because they already know which one is the A-Master.
Approach and Implementation
Figure 28. Visual representation of the color discriminationtest.
● Semantic Scales Test
The last phase consists of evaluating the A-master and the parameters in a deeper way using semantic scales. Semantic scales make it possible to transform these abstract concepts into tangible, concrete and measurable values. Because everything that can be measured can be improved. (See Chapter 3.9.1)
It is a useful tool to translate words and comments into numerical values to find correlations between different phenomena. The scale values and the terms used have been based on CIELab, which is the system that Volvo uses. (See Chapter 3.12)
These semantic scales are divided into reflection, color and defects. In the
reflection group the A-master will be evaluated in terms of gloss, haze and metallic depth. In the color group, the A-master will be evaluated in terms of Blue-Yellow, Red-Green, Dark-Light. The “defects” semantic scales will be evaluated just with Volvo Experts in order to find correlations between different parameters.
At the end of the study, the user will be thanked for their participation and will be asked for the data of: Name, city, age, sex, profession, hobbies and eyes condition.
Figure 29. Reflexion semantic scales
Figure 30. Color semantic scales
Approach and Implementation
4.4 Deliver
The last phase of the project (Deliver) corresponds to the sections "Result" and "Conclusions" of this writing.
5
Result
5.1 Soft Metrology
5.1.1 Population
The study was carried out in three different locations with three different population groups. (Van Gool and Ramos Lapesa, 2021)
● Gothenburg, 17 professional workers at Volvo. ● Halmstad, 15 engineers and university students.
● Jonkoping, 15 design professionals and design students.
The total population reaches 47 users aged between 19 and 60 years of mixed gender.
Result
Figure 33. Gender of the total population: 32 menand 15 women.
Figure 34. Farnsworth Munsell 100 Hue Test Score for the total population.
Most of the participants obtained a perfect score of 0, and those who did not between 2 and 4 which is almost perfect. (Van Gool and Ramos Lapesa, 2021)
The number of test persons might not give a statistical accuracy. However there is room for another test with a larger population in order to get statistical accuracy.
5.1.2 Affective Test
The generated graphs show the users' preference by ordering the samples from most disliked to most liked according to the mean obtained.
Volvo:
In the case of Volvo the top 3 preferred samples are D, F, and G. With D being the most preferred. (Van Gool and Ramos Lapesa, 2021)
The top 3 least preferred samples are E, C, A with E being the most detested. The A-master (A) has been placed as one of the most detested.
Figure 35. Maxdiff variation test result for Volvopopulation.
Halmstad:
In the case of Halmstad the top 3 preferred samples are F, D and B. With F being the most preferred.
The top 3 least preferred samples are E, C, G with E being the most detested with a big difference.
Result
Figure 36. Maxdiff variation test result for Halmstadpopulation.
Jönköping:
In the case of Jönköping the top 3 preferred samples are B, F and D. With B being the most preferred.
The top 3 least preferred samples are G, E, C with G being the most detested.
The A-master (A) has been placed in the middle. (Van Gool and Ramos Lapesa, 2021)
Total:
The final result shows that the top 3 preferences are D, B and F. With D being the most preferred with very little difference with respect to B.
The top 3 of the least preferred are composed of E,C, A. With E being by far the least preferred.
It should be noted that A-Master (A) is in this group. (Van Gool and Ramos Lapesa, 2021)
Figure 38. Maxdiff variation test result for the totalpopulation.
The preferences were also compared with the different suppliers and type of coating. (Figure 39)
The samples have been placed on the X-axis and the different finishes and their respective suppliers have been placed on the Y-axis.
There is also a third dimension, the color, based on the marginal utility that represents the preference being green very preferred and red little preferred.
It can be clearly seen that the preferred samples belong to Atotech and AMB, and the least preferred finishes belong to POP and Plasman, with Plasman being the supplier of the least preferred sample.
Noted that A-Master (A) belongs to the least preferred and that Chrome VI has not been as well accepted as other sustainable alternatives. (Van Gool and Ramos Lapesa, 2021)
Result
Figure 39. Preference compared to coating processes.
In the affective test, users were asked to comment on each of the samples in each of the iterations, approximately 1400 total comments were obtained.
These comments have been grouped by sample so that a comprehensive description of the sample has been obtained at a perceptual level. (See Appendix 5)
To show this data in a more holistic way, the keywords have been extracted from each of the comments, such as "high-quality", "nice" or "matt" and they have been processed with a software that generates word clouds. showing the most repeated words with a larger size.
In this way, a table has been generated with the different word clouds located according to the type of population and the type of sample. (VanGool and Ramos Lapesa, 2021)
This graph allows us to know in a simple way the reasons why some samples are more or less preferred and the differences between what one population perceives or another. It also allows us to see what the perceived general appearance of each sample is by combining the three populations. (Van Gool and Ramos Lapesa, 2021)
Figure 41. Word clouds characterization and preference of each sample based on each population comments.
In the graph above we can see that the perceptions among the user groups are slightly different.
For Jonkoping what stands out most about the A-Master is its quality and metallic appearance.
However, for Halmstad it is too bright and clear.
Volvo, on the other hand, perceives it as Scandinavian and good although its reflection has uneven colors.
As for sample B, Jönköping and Halmstad have a similar perception, where the most striking feature is its neutrality and matte finish. Volvo uses other words such as "light", "plain" and "satin silk" to refer to the same thing. There seems to be more unanimity in the perception of B. (Van Gool and Ramos Lapesa, 2021)
C is another sample with unanimity in the comments being dark and blue-green for most users. However it seems that Volvo mostly sees green and the untrained eye population mostly sees blue.
Result
All agree that D is one of the brightest and most metallic looking samples. Overall it is perceived as high quality.
E is undoubtedly perceived as the darkest and greenest blue-green. Again, we find the phenomenon that while Volvo sees green, the rest of the population perceives it as blue. F is perceived as yellowish, warm and matte by the majority of the population, and although these are not the attributes usually present in chrome, it generates a positive perception. (Van Gool and Ramos Lapesa, 2021)
G is by far the brightest sample and is even perceived as too bright, generating rejection.
5.1.3 Descriptive Test
A heat map has been used as the best way to represent the results in the descriptive test. The X-axis shows the samples and the Y-axis shows the position from 1 to 7, with 1 being low brightness/blue and 7 being high brightness/yellow.
The meaning of the color of the boxes (red-gray-blue) is represented in the legend on the right of the graphs. (Van Gool and Ramos Lapesa, 2021)
The redder the color, the more times that sample has been placed in that position.
For the graph of the distribution according to glossiness (Figure 42) we obtain the following results: (Van Gool and Ramos Lapesa, 2021)
A-Master 44/47 times has been positioned at 5. Sample D 45/47 times has been positioned at 6.
Figure 42. Gloss sorting
The following chart shows the distribution in terms of color:
Figure 43. Color sorting
Result
Since these data could be not very clear, new graphics were generated summarising the sorting and adding the preference dimension (marginal utility) in color green and red, being green as preferred and red as not preferred. (Van Gool and Ramos Lapesa, 2021) In the graphs the samples have been placed on the X-axis sorted either by gloss (from less gloss to more gloss) or by color (from more bluish to more yellowish).
Volvo:
For Volvo E and D are the samples most similar to the A-Master in terms of gloss. D being the most preferred and E the most detested. (Van Gool and Ramos Lapesa, 2021) There does not seem to be a correlation between preference and gloss.
Figure 44. Gloss descriptive test result for Volvo.
Jönköping and Halmstad:
For Jönköping and Halmstad the way to sort the samples in terms of gloss is exactly the same. F and D are the samples most similar to the A-Master in terms of gloss, both preferred. However, due to uneven distribution in terms of preference, there does not seem to be a correlation between preference and gloss. (Van Gool and Ramos Lapesa, 2021)
Figure 45. Gloss descriptive test result for Jönköping.
Figure 46. Gloss descriptive test result for Halmstad.
Total:
The graph with the set of all data shows that apparently the samples most similar to the A-Master in terms of brightness are E and D. The most detested and the most preferred. In general the preference distribution is uneven and does not show a pattern. There does not appear to be a correlation between preference and brightness. (Van Gool and Ramos Lapesa, 2021)
Result
Figure 47. Gloss descriptive test result for all population.
Volvo:
In terms of color, Volvo has mostly placed G and C as the most similar in terms of brightness with respect to the A-Master.
There is also a seamless transition of preference and brightness. There seems to be a strong correlation between color and preference. (Van Gool and Ramos Lapesa, 2021)
