A Guide to Understanding Color Communication
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Color Theory for Painting Video: Color Perception
Color Theory For Painting Video: Color Perception • http://www.ted.com/talks/lang/eng/beau_lotto_optical_illusions_show_how_we_see.html • Experiment • http://www.youtube.com/watch?v=y8U0YPHxiFQ Intro to color theory • http://www.youtube.com/watch?v=059-0wrJpAU&feature=relmfu Color Theory Principles • The Color Wheel • Color context • Color Schemes • Color Applications and Effects The Color Wheel The Color Wheel • A circular diagram displaying the spectrum of visible colors. The Color Wheel: Primary Colors • Primary Colors: Red, yellow and blue • In traditional color theory, primary colors can not be mixed or formed by any combination of other colors. • All other colors are derived from these 3 hues. The Color Wheel: Secondary Colors • Secondary Colors: Green, orange and purple • These are the colors formed by mixing the primary colors. The Color Wheel: Tertiary Colors • Tertiary Colors: Yellow- orange, red-orange, red-purple, blue-purple, blue-green & yellow-green • • These are the colors formed by mixing a primary and a secondary color. • Often have a two-word name, such as blue-green, red-violet, and yellow-orange. Color Context • How color behaves in relation to other colors and shapes is a complex area of color theory. Compare the contrast effects of different color backgrounds for the same red square. Color Context • Does your impression od the center square change based on the surround? Color Context Additive colors • Additive: Mixing colored Light Subtractive Colors • Subtractive Colors: Mixing colored pigments Color Schemes Color Schemes • Formulas for creating visual unity [often called color harmony] using colors on the color wheel Basic Schemes • Analogous • Complementary • Triadic • Split complement Analogous Color formula used to create color harmony through the selection of three related colors which are next to one another on the color wheel. -
Color Models
Color Models Jian Huang CS456 Main Color Spaces • CIE XYZ, xyY • RGB, CMYK • HSV (Munsell, HSL, IHS) • Lab, UVW, YUV, YCrCb, Luv, Differences in Color Spaces • What is the use? For display, editing, computation, compression, …? • Several key (very often conflicting) features may be sought after: – Additive (RGB) or subtractive (CMYK) – Separation of luminance and chromaticity – Equal distance between colors are equally perceivable CIE Standard • CIE: International Commission on Illumination (Comission Internationale de l’Eclairage). • Human perception based standard (1931), established with color matching experiment • Standard observer: a composite of a group of 15 to 20 people CIE Experiment CIE Experiment Result • Three pure light source: R = 700 nm, G = 546 nm, B = 436 nm. CIE Color Space • 3 hypothetical light sources, X, Y, and Z, which yield positive matching curves • Y: roughly corresponds to luminous efficiency characteristic of human eye CIE Color Space CIE xyY Space • Irregular 3D volume shape is difficult to understand • Chromaticity diagram (the same color of the varying intensity, Y, should all end up at the same point) Color Gamut • The range of color representation of a display device RGB (monitors) • The de facto standard The RGB Cube • RGB color space is perceptually non-linear • RGB space is a subset of the colors human can perceive • Con: what is ‘bloody red’ in RGB? CMY(K): printing • Cyan, Magenta, Yellow (Black) – CMY(K) • A subtractive color model dye color absorbs reflects cyan red blue and green magenta green blue and red yellow blue red and green black all none RGB and CMY • Converting between RGB and CMY RGB and CMY HSV • This color model is based on polar coordinates, not Cartesian coordinates. -
Chapter 6 : Color Image Processing
Chapter 6 : Color Image Processing CCU, Taiwan Wen-Nung Lie Color Fundamentals Spectrum that covers visible colors : 400 ~ 700 nm Three basic quantities Radiance : energy that flows from the light source (measured in Watts) Luminance : a measure of energy an observer perceives from a light source (in lumens) Brightness : a subjective descriptor difficult to measure CCU, Taiwan Wen-Nung Lie 6-1 About human eyes Primary colors for standardization blue : 435.8 nm, green : 546.1 nm, red : 700 nm Not all visible colors can be produced by mixing these three primaries in various intensity proportions Cones in human eyes are divided into three sensing categories 65% are sensitive to red light, 33% sensitive to green light, 2% sensitive to blue (but most sensitive) The R, G, and B colors perceived by CCU, Taiwan human eyes cover a range of spectrum Wen-Nung Lie 6-2 Primary and secondary colors of light and pigments Secondary colors of light magenta (R+B), cyan (G+B), yellow (R+G) R+G+B=white Primary colors of pigments magenta, cyan, and yellow M+C+Y=black CCU, Taiwan Wen-Nung Lie 6-3 Chromaticity Hue + saturation = chromaticity hue : an attribute associated with the dominant wavelength or dominant colors perceived by an observer saturation : relative purity or the amount of white light mixed with a hue (the degree of saturation is inversely proportional to the amount of added white light) Color = brightness + chromaticity Tristimulus values (the amount of R, G, and B needed to form any particular color : X, Y, Z trichromatic -
COLOR SPACE MODELS for VIDEO and CHROMA SUBSAMPLING
COLOR SPACE MODELS for VIDEO and CHROMA SUBSAMPLING Color space A color model is an abstract mathematical model describing the way colors can be represented as tuples of numbers, typically as three or four values or color components (e.g. RGB and CMYK are color models). However, a color model with no associated mapping function to an absolute color space is a more or less arbitrary color system with little connection to the requirements of any given application. Adding a certain mapping function between the color model and a certain reference color space results in a definite "footprint" within the reference color space. This "footprint" is known as a gamut, and, in combination with the color model, defines a new color space. For example, Adobe RGB and sRGB are two different absolute color spaces, both based on the RGB model. In the most generic sense of the definition above, color spaces can be defined without the use of a color model. These spaces, such as Pantone, are in effect a given set of names or numbers which are defined by the existence of a corresponding set of physical color swatches. This article focuses on the mathematical model concept. Understanding the concept Most people have heard that a wide range of colors can be created by the primary colors red, blue, and yellow, if working with paints. Those colors then define a color space. We can specify the amount of red color as the X axis, the amount of blue as the Y axis, and the amount of yellow as the Z axis, giving us a three-dimensional space, wherein every possible color has a unique position. -
Cielab Color Space
Gernot Hoffmann CIELab Color Space Contents . Introduction 2 2. Formulas 4 3. Primaries and Matrices 0 4. Gamut Restrictions and Tests 5. Inverse Gamma Correction 2 6. CIE L*=50 3 7. NTSC L*=50 4 8. sRGB L*=/0/.../90/99 5 9. AdobeRGB L*=0/.../90 26 0. ProPhotoRGB L*=0/.../90 35 . 3D Views 44 2. Linear and Standard Nonlinear CIELab 47 3. Human Gamut in CIELab 48 4. Low Chromaticity 49 5. sRGB L*=50 with RGB Numbers 50 6. PostScript Kernels 5 7. Mapping CIELab to xyY 56 8. Number of Different Colors 59 9. HLS-Hue for sRGB in CIELab 60 20. References 62 1.1 Introduction CIE XYZ is an absolute color space (not device dependent). Each visible color has non-negative coordinates X,Y,Z. CIE xyY, the horseshoe diagram as shown below, is a perspective projection of XYZ coordinates onto a plane xy. The luminance is missing. CIELab is a nonlinear transformation of XYZ into coordinates L*,a*,b*. The gamut for any RGB color system is a triangle in the CIE xyY chromaticity diagram, here shown for the CIE primaries, the NTSC primaries, the Rec.709 primaries (which are also valid for sRGB and therefore for many PC monitors) and the non-physical working space ProPhotoRGB. The white points are individually defined for the color spaces. The CIELab color space was intended for equal perceptual differences for equal chan- ges in the coordinates L*,a* and b*. Color differences deltaE are defined as Euclidian distances in CIELab. This document shows color charts in CIELab for several RGB color spaces. -
Color Difference Delta E - a Survey
See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/236023905 Color difference Delta E - A survey Article in Machine Graphics and Vision · April 2011 CITATIONS READS 12 8,785 2 authors: Wojciech Mokrzycki Maciej Tatol Cardinal Stefan Wyszynski University in Warsaw University of Warmia and Mazury in Olsztyn 157 PUBLICATIONS 177 CITATIONS 5 PUBLICATIONS 27 CITATIONS SEE PROFILE SEE PROFILE All content following this page was uploaded by Wojciech Mokrzycki on 08 August 2017. The user has requested enhancement of the downloaded file. Colour difference ∆E - A survey Mokrzycki W.S., Tatol M. {mokrzycki,mtatol}@matman.uwm.edu.pl Faculty of Mathematics and Informatics University of Warmia and Mazury, Sloneczna 54, Olsztyn, Poland Preprint submitted to Machine Graphic & Vision, 08:10:2012 1 Contents 1. Introduction 4 2. The concept of color difference and its tolerance 4 2.1. Determinants of color perception . 4 2.2. Difference in color and tolerance for color of product . 5 3. An early period in ∆E formalization 6 3.1. JND units and the ∆EDN formula . 6 3.2. Judd NBS units, Judd ∆EJ and Judd-Hunter ∆ENBS formulas . 6 3.3. Adams chromatic valence color space and the ∆EA formula . 6 3.4. MacAdam ellipses and the ∆EFMCII formula . 8 4. The ANLab model and ∆E formulas 10 4.1. The ANLab model . 10 4.2. The ∆EAN formula . 10 4.3. McLaren ∆EMcL and McDonald ∆EJPC79 formulas . 10 4.4. The Hunter color system and the ∆EH formula . 11 5. ∆E formulas in uniform color spaces 11 5.1. -
Color Gamut of Halftone Reproduction*
Color Gamut of Halftone Reproduction* Stefan Gustavson†‡ Department of Electrical Engineering, Linkøping University, S-581 83 Linkøping, Sweden Abstract tern then gets attenuated once more by the pattern of ink that resides on the surface, and the finally reflected light Color mixing by a halftoning process, as used for color is the result of these three effects combined: transmis- reproduction in graphic arts and most forms of digital sion through the ink film, diffused reflection from the hardcopy, is neither additive nor subtractive. Halftone substrate, and transmission through the ink film again. color reproduction with a given set of primary colors is The left-hand side of Fig. 2 shows an exploded view of heavily influenced not only by the colorimetric proper- the ink layer and the substrate, with the diffused reflected ties of the full-tone primaries, but also by effects such pattern shown on the substrate. The final viewed image as optical and physical dot gain and the halftone geom- is a view from the top of these two layers, as shown to etry. We demonstrate that such effects not only distort the right in Fig. 2. The dots do not really increase in the transfer characteristics of the process, but also have size, but they have a shadow around the edge that makes an impact on the size of the color gamut. In particular, a them appear larger, and the image is darker than what large dot gain, which is commonly regarded as an un- would have been the case without optical dot gain. wanted distortion, expands the color gamut quite con- siderably. -
Explicit Image Detection Using Ycbcr Space Color Model As Skin Detection
Applications of Mathematics and Computer Engineering Explicit Image Detection using YCbCr Space Color Model as Skin Detection JORGE ALBERTO MARCIAL BASILIO1, GUALBERTO AGUILAR TORRES2, GABRIEL SÁNCHEZ PÉREZ3, L. KARINA TOSCANO MEDINA4, HÉCTOR M. PÉREZ MEANA5 Sección de Estudios de Posgrados e Investigación 1Escuela Superior de Ingeniería Mecánica y Eléctrica Unidad Culhuacan Santa Ana #1000 Col. San Francisco Culhuacan, Del. Coyoacán C.P. 04430 MEXICO CITY [email protected], [email protected], [email protected], [email protected], [email protected] Abstract: - In this paper a novel way to detect explicit content images is proposed using the YCbCr space color, moreover the color pixels percentage that are within the image is calculated which are susceptible to be a tone skin. The main goal to use this method is to apply to forensic analysis or pornographic images detection on storage devices such as hard disk, USB memories, etc. The results obtained using the proposed method are compared with Paraben’s Porn Detection Stick software which is one of the most commercial devices used for detecting pornographic images. The proposed algorithm achieved identify up to 88.8% of the explicit content images, and 5% of false positives, the Paraben’s Porn Detection Stick software achieved 89.7% of effectiveness for the same set of images but with a 6.8% of false positives. In both cases were used a set of 1000 images, 550 natural images, and 450 with highly explicit content. Finally the proposed algorithm effectiveness shows that the methodology applied to explicit image detection was successfully proved vs Paraben’s Porn Detection Stick software. -
ROCK-COLOR CHART with Genuine Munsell® Color Chips
geological ROCK-COLOR CHART with genuine Munsell® color chips Produced by geological ROCK-COLOR CHART with genuine Munsell® color chips 2009 Year Revised | 2009 Production Date put into use This publication is a revision of the previously published Geological Society of America (GSA) Rock-Color Chart prepared by the Rock-Color Chart Committee (representing the U.S. Geological Survey, GSA, the American Association of Petroleum Geologists, the Society of Economic Geologists, and the Association of American State Geologists). Colors within this chart are the same as those used in previous GSA editions, and the chart was produced in cooperation with GSA. Produced by 4300 44th Street • Grand Rapids, MI 49512 • Tel: 877-888-1720 • munsell.com The Rock-Color Chart The pages within this book are cleanable and can be exposed to the standard environmental conditions that are met in the field. This does not mean that the book will be able to withstand all of the environmental conditions that it is exposed to in the field. For the cleaning of the colored pages, please make sure not to use a cleaning agent or materials that are coarse in nature. These materials could either damage the surface of the color chips or cause the color chips to start to delaminate from the pages. With the specifying of the rock color it is important to remember to replace the rock color chart book on a regular basis so that the colors being specified are consistent from one individual to another. We recommend that you mark the date when you started to use the the book. -
Ph.D. Thesis Abstractindex
COLOR REPRODUCTION OF FACIAL PATTERN AND ENDOSCOPIC IMAGE BASED ON COLOR APPEARANCE MODELS December 1996 Francisco Hideki Imai Graduate School of Science and Technology Chiba University, JAPAN Dedicated to my parents ii COLOR REPRODUCTION OF FACIAL PATTERN AND ENDOSCOPIC IMAGE BASED ON COLOR APPEARANCE MODELS A dissertation submitted to the Graduate School of Science and Technology of Chiba University in partial fulfillment of the requirements for the degree of Doctor of Philosophy by Francisco Hideki Imai December 1996 iii Declaration This is to certify that this work has been done by me and it has not been submitted elsewhere for the award of any degree or diploma. Countersigned Signature of the student ___________________________________ _______________________________ Yoichi Miyake, Professor Francisco Hideki Imai iv The undersigned have examined the dissertation entitled COLOR REPRODUCTION OF FACIAL PATTERN AND ENDOSCOPIC IMAGE BASED ON COLOR APPEARANCE MODELS presented by _______Francisco Hideki Imai____________, a candidate for the degree of Doctor of Philosophy, and hereby certify that it is worthy of acceptance. ______________________________ ______________________________ Date Advisor Yoichi Miyake, Professor EXAMINING COMMITTEE ____________________________ Yoshizumi Yasuda, Professor ____________________________ Toshio Honda, Professor ____________________________ Hirohisa Yaguchi, Professor ____________________________ Atsushi Imiya, Associate Professor v Abstract In recent years, many imaging systems have been developed, and it became increasingly important to exchange image data through the computer network. Therefore, it is required to reproduce color independently on each imaging device. In the studies of device independent color reproduction, colorimetric color reproduction has been done, namely color with same chromaticity or tristimulus values is reproduced. However, even if the tristimulus values are the same, color appearance is not always same under different viewing conditions. -
Color Mixing Ratios
Colour Mixing: Ratios Color Theory with Tracy Moreau Learn more at DecoArt’s Art For Everyone Learning Center www.tracymoreau.net Primary Colours In painting, the three primary colours are yellow, red, and blue. These colors cannot be created by mixing other colours. They are called primary because all other colours are derived from them. Mixing Primary Colours Creates Secondary Colours If you combine two primary colours you get a secondary colour. For example, red and blue make violet, yellow and red make orange, and blue and yellow make green. If you mix all of the primary colours together you get black. The Mixing Ratio for Primary Colours To get orange, you mix the primary colours red and yellow. The mixing ratio of these two colours determines which shade of orange you will get after mixing. For example, if you use more red than yellow you will get a reddish-orange. If you add more yellow than red you will get a yellowish-orange. Experiment with the shades you have to see what you can create. Try out different combinations and mixing ratios and keep a written record of your results so that you can mix the colours again for future paintings. www.tracymoreau.net Tertiary Colours By mixing a primary and a secondary colour or two secondary colours you get a tertiary colour. Tertiary colours such as blue-lilac, yellow-green, green-blue, orange-yellow, red-orange, and violet-red are all created by combining a primary and a secondary colour. The Mixing Ratios of Light and Dark Colours If you want to darken a colour, you only need to add a small amount of black or another dark colour. -
Accurately Reproducing Pantone Colors on Digital Presses
Accurately Reproducing Pantone Colors on Digital Presses By Anne Howard Graphic Communication Department College of Liberal Arts California Polytechnic State University June 2012 Abstract Anne Howard Graphic Communication Department, June 2012 Advisor: Dr. Xiaoying Rong The purpose of this study was to find out how accurately digital presses reproduce Pantone spot colors. The Pantone Matching System is a printing industry standard for spot colors. Because digital printing is becoming more popular, this study was intended to help designers decide on whether they should print Pantone colors on digital presses and expect to see similar colors on paper as they do on a computer monitor. This study investigated how a Xerox DocuColor 2060, Ricoh Pro C900s, and a Konica Minolta bizhub Press C8000 with default settings could print 45 Pantone colors from the Uncoated Solid color book with only the use of cyan, magenta, yellow and black toner. After creating a profile with a GRACoL target sheet, the 45 colors were printed again, measured and compared to the original Pantone Swatch book. Results from this study showed that the profile helped correct the DocuColor color output, however, the Konica Minolta and Ricoh color outputs generally produced the same as they did without the profile. The Konica Minolta and Ricoh have much newer versions of the EFI Fiery RIPs than the DocuColor so they are more likely to interpret Pantone colors the same way as when a profile is used. If printers are using newer presses, they should expect to see consistent color output of Pantone colors with or without profiles when using default settings.