NIST Appearance -- March 2000 Workshop Presentations

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Workshop on Metrology and Modeling of Color and Appearance -- Workshop Presentations

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Color and Appearance Attributes Richard Harold, Keynote Speaker Color and Appearance Consulting LLC	*Requests for presentation material may be directed to:* Richard Harold Color & Appearance Consulting LLC 711 Herndon Woods Court Herndon, VA 20170 Tel: 703-709-5453 Email: rwharold@worldnet.att.net
Abstract
The appearance of an object is the result of a complex interaction of the light incident on the object, the optical characteristics of the object, and human perception. The appearance of manufactured products, given that they will fulfill the intended purpose, is one of the most important commercial attributes. Appearance often determines the acceptability of a product to its seller, and ultimately to the consumer or end-user. The quality and consistancy of the appearance of a product is psychologically related to its expected performance and useful life. It therefore determines its acceptance (or rejection) by potential purchasers.
This paper describes the interaction of light with objects -- reflection, transmission, scattering, absorption, or a combination of these phenomena, which result in the human perception of appearance. The three elements of human perception -- light, object and observer, can be quantified and further reduced to a set of colorimetric specifications. These colorimetric values can be converted into a variety of color and difference scales which can be used for numerical specifications of "acceptability". Some of the more recent developments in this area are reviewed.
Various methods of measurement are highlighted including the basic CIE optical geometrics for colorimeters and spectrophotometers, gloss meters, goniophotometers, gonio-spectrophotometers and image analysis. However all the methods of characterization require careful attention to specimen selection, handling, measurement techniques, instrument calibration, standardization and verification. A lot to think about. But it is worth the effort.
By choosing the proper instruments and following standard techniques of measurement, materials can be characterized for a variety of illuminating/viewing conditions. This information, along with standardized conditions for visual inspection, will provide a means for more objective appearance communication thus minimizing disagreements and product returns.
Richard W. Harold
Richard W. Harold is a consultant on color and appearance technology. He manages the group, Color and Appearance Consulting LLC, and is a member of Avian Group_usa, an optical design and development consortium. The range of services include color and appearance measurement and applications engineering, consulting, custom training programs, design and development of systems and subsystems for the measurement of transmittance, reflectance, radiance, irradiance, color, fluorescence, and imaging. Also offering custom designed programming and software engineering for a broad variety of color and appearance applications.
Mr. Harold received his B. S. degree in chemistry from the University of South Florida (Tampa) in 1965. He was a research chemist for the Mary Carter Paint Company (Tampa, Florida) from 1965-1967 where he was responsible for paint formulation research and color control. From 1967-1970, he was the Color Control Coordinator for the Harshaw Chemical Company (today know as Engelhard Corporation), Color Pigment and Dye Division (Louisville, Kentucky), where he was responsible for implementing color measurement and developing color control tolerances. Most recently, he was Associate Director at Hunter Associates Laboratory (Reston, Virginia), a manufacturer of color and appearance instrumentation, from 1970 – 1998 where he was responsible for applications engineering, color and appearance research, consulting, and educational programs.
Mr. Harold is a Chartered Colourist and Fellow of the Society of Dyers and Colourists (U. K.). He is Chairman of the International Organization for Standardization (ISO) Committee TC 38/SC-1 and Convener (Chairman) of Working Group 7 (Colour Measurement). He is Chairman of the AATCC International Test Methods Committee (C2-S1) and Chairman of the USA Technical Advisory Group (TAG) for ISO TC 38. He is the Liaison Officer to ISO TC-87 (Colour Notations). He is Vice-Chairman of the American Society for Testing and Materials (ASTM) Committee E12 on Color and Appearance. He is actively involved in the work of ASTM, ISO, the Inter-Society Color Council (ISCC), the Committee for Graphic Arts Technologies Standards (CGATS), and the U.S. National Committee of the C.I.E.
Mr. Harold has lectured extensively and has published numerous technical papers on the subjects of color and appearance technology and has co-authored with Richard S. Hunter, The Measurement of Appearance, Second Edition.

Evaluating Color Instrument Performance Using Large Scale Studies
Charles G. Leete
Collaborative Testing Services, Inc.

Abstract

Using data from over 275 instruments in an ongoing large-scale color and appearance interlaboratory testing program, an analysis was made of instrument performance. Analysis conditions were sphere geometry, Illuminant D65, and 10° observer with CIE L^*, a^*, b^* color space. Matte samples were used, and the specular component was not a significant factor. Two major conclusions were reached: (1) there is very good agreement among instruments on color difference determinations, and (2) there is very poor agreement among instruments in reporting individual L^*, a^*, b^* values. Examples are given to illustrate the performance on color difference with typical between laboratory standard deviations values of 0.08 or less. As there are no national color standards, techniques are shown to determine consensus agreement for individual L^*, a^*, b^* values. Using a large number of instruments, the techniques tend to have an almost surgical-like precision in determining performance. However, the range of consensus results for instruments within 95% control limits is large enough to prohibit the specification of color “by the number.” Approximately 40 laboratories have been accredited for color measurements. International recognition of their accreditation is starting to require that their instrument standards are obtained from either a primary national laboratory, an accredited calibration standard supplier or an accredited field calibration service supplier. If and when such standards or services are available there should be a major impact on instrument.

Charles Leete

Charles Leete is the president of Collaborative Testing Services, Inc., an interlaboratory testing firm now entering its 30^thyear of operations. Both CTS and its Color and Appearance testing program on which today’s presentation is based trace their roots to the National Bureau of Standards, now NIST, where Mr. Leete was based as a research associate on behalf of several trade and professional associations. Among his other relevant experiences he has published a number of articles, taught courses on color and appearance measurement, and designed an automotive paint chip collection for hit-and-run analysis by forensic laboratories. Charles Leete has also been a paint chemist, technical services specialist for a pigment and dye manufacturer, and director of applications and marketing for an instrument firm.

Color Matching Problems in the Paint Industry *James Roberts* Duron, Inc.	View Presentation

Abstract
As consumers become more and more technically competent, they expect the world around them to meet rapidly changing expectations. No longer will a single color formula book work for all quality levels, all sheen levels and for both oil and latex paints. Customers EXPECT the match that is mixed in the store to be perfect, and will shop for a store that has computer color matching equipment because the matches will be “much better than store personnel can do.” In the cases where the employees are new or untrained that may in fact be true. However, nothing available on the market today will match colors as well as the human eye and an experienced paint matcher.
This talk will discuss a number of the issues that get in the way of achieving that perfect color formula time after time. There are a number of uncontrolled variables that stores (and paint labs) face every day that prevent the expected perfection. Tint equipment, shakers, colorant variation, tint base variation, color acceptance issues, and the color formulation software itself can all have negative influences on the quality of the store match. These same issues often interfere at the lab level, where color formulas are developed for the stores.
James Roberts
James Roberts received a B.S. Degree in 1975 from Worcester Polytechnic Institute in Chemical Engineering/ Life Sciences, an Interdisciplinary degree. He worked for Cabot Stains in Chelsea, MA 1975 to 1983, formulating exterior wood stains and running the QC Lab. In 1984 he moved to Baltimore to work for Sportec International, a manufacturer of latex tennis court coatings and urethane running track systems. He left Sportec to work for Duron Paints in 1988. He has held various positions at Duron, from Director of Manufacturing to Formulation Chemist to his current position as Director of Color Systems, which he has held for the last 6 years. He regularly attends the Coatings Federation Society Meetings in Baltimore, and holds Chairholder status with the Color Marketing Group. He is also Networking Chairman for that Baltimore Society.

Appearance Attributes of Metallic Paints and Plastics*
C. S. McCamy
Wappingers Falls, New York

Abstract

Metallic paints and plastics have been widely used, particularly in the automotive industry, for half a century, but relevant scientific concepts and terminology to describe the appearance of these materials are still evolving. In this context, the term “metallic” is used in a special sense, to identify paints and plastics containing metal flake pigments, rather than in the conventional sense, to identify things made of metal. The attributes of appearance of these materials are of two kinds, those observed at a distance of several meters and those observed at reading distance. The first kind may be called “macro appearance”, the second “micro appearance.”

The primary macro appearance attributes of metallic materials are luster and goniochromism. Luster is the appearance of bright reflection at and near the specular angle. This appearance attribute is also characteristic of satin textiles and some paints without metal flake pigments. Goniochromism is a color variation with angles of illumination and viewing that is not perceived as luster. This attribute is also observed on a textile called “changeable taffeta.” Luster and goniochromism are quantified by illuminating the surface at a fixed angle to the normal, usually 45º, and measuring the light reflected at various angles, usually measured from the specular direction and called “aspecular angles.” A number of portable instruments to make such measurements quickly and conveniently and special viewing booths to observe specimens under several sets of angular conditions are available commercially. There are active programs to standardize such observations and measurements, in the American Society for Testing and Materials (ASTM) and in a joint BAM and DIN Committee in Germany.

When metallic materials are viewed at reading distance, they exhibit a number of interesting appearance attributes, including glitter, glints, depth, coherence glitter, binocular luster, binocular glitter, and binocular mottle. Webster's unabridged dictionary says the term “glitter” means “to shine resplendently ... by reflection with many quick small flashes of brilliant light or with a hard bright ... metallic luster made up of many small scattered rapidly appearing and disappearing points of light.” The temporal changes referred to arise in casual observations as the geometric conditions of observation change. The “points of light” that result from specular reflection from individual flakes are called “glints.” The “depth” of a material may be observed if individual flakes are large enough to be perceived and located binocularly. Neutral colored metallic materials with very fine flakes may exhibit a very small-scale colored glitter, when closely observed in direct sunlight. This phenomenon results from the fact that sunlight is spatially coherent over a very short distance, permitting interference between the light beams reflected by nearby flakes. This attribute is called “coherence glitter.”

The color of a metallic material may change so much with change in angle of view that the two eyes may perceive noticeably different colors. The binocular effect is called “binocular luster.” In the same way, when a metallic material is illuminated by a light subtending a small angle, the two eyes may see different sets of glints, giving rise to a fascinating visual perception, called “binocular glitter.” The same phenomenon on a larger scale, where the two eyes perceive different clusters of flakes, gives rise to the perception of a sort of texture in depth, which I have called “binocular mottle.” The techniques developed in photographic science to characterize the graininess of photographs can be applied to metallic materials. Likewise, the techniques developed to characterize images can be applied to measurements of luster. Metallic materials usually have a glossy surface, but the flakes beneath that surface give the appearance of a “subsurface” that has attributes unlike a smooth glossy surface.

*This presentation is based on two published papers: C.S. McCamy, Observation and Measurement of the Appearance of Metallic Materials, Part I. Macro Appearance, Color Res. Appl., 21, 292 – 304 (1996) and C.S. McCamy, Observation and Measurement of the Appearance of Metallic Materials, Part II. Micro Appearance, Color Res. Appl., 23, 362 – 373 (1998).

Cal McCamy

Mr. McCamy was in the U.S. Navy, 1942-1947, attaining the rank of Lieutenant, j.g. He received a B.S. in Chemical Engineering and M.S. in Physics at the University of Minnesota and taught mathematics there, 1947-1950. He taught physics and did early research in colorant formulation at Clemson University, 1950-1952.

At the National Bureau of Standards, 1952-1957, he established principles of fire detection in aircraft engines, discovered the mechanism of fire extinguishment by dry chemicals, and studied the hazards of liquid oxygen. As Chief of the Photographic Research Section and then the Image Optics and Photography Section, 1958-1970, he conducted research on precise measurement of transmission and reflection, image structure, satellite photography, photography at extreme reduction, optical information theory, optical filters, color perception, and preservation of microfilms. He designed hands-on experiments for the U.S. Science Exhibit at the Seattle World’s Fair.

As Vice President for Research of the Macbeth Division of Kollmorgen, 1970-1990, he conducted research on optical design, precise transmission measurements, color measurement, optical filter design, simulation of daylight, geometric attributes of appearance, densitometry in photography and color printing, color order systems, color standards, and related mathematics. He designed the Macbeth ColorChecker Color Rendition Chart™ used internationally to evaluate color imaging systems of all kinds.

He was a member of the National Research Council. At the request of Congress, in 1978 he analyzed photographs and x-rays related to the assassination of President Kennedy and testified before the House Select Committee on Assassinations. His method of identifying images of firearms is used routinely by the FBI.

He has been active in national and international standardization of photography, color printing, and color science, since 1957, chairing committees of the American National Standards Institute, the American Society for Testing and Materials, the International Commission on Illumination (CIE), and the International Organization for Standardization (ISO). He wrote the spectral specifications for optical character recognition for the banking industry and the Universal Product Code for the grocery and other retail industries.

He is on the Advisory Board of the Munsell Color Science Laboratory at the Rochester Institute of Technology, and was Adjunct Professor at Rensselaer Polytechnic Institute. He was president of the Kollmorgen Foundation and trustee of the Munsell Foundation, both of which awarded doctoral scholarships in color science. He presented seminars on color science around the world, fourteen in Brazil alone.

He has published over a hundred scientific papers. He was an officer or board member of several scientific societies. He was elected fellow of the Optical Society of America, Society of Photographic Scientists and Engineers, Royal Photographic Society of Great Britain, Society of Motion Picture and Television Engineers, and the Washington Academy of Sciences and has been honored for his lectures. He was elected Honorary Member of the Inter-Society Color Council and the Hong Kong Society of Dyers and Colorists, Life Member of the U.S. Committee of the CIE, and member of the New York Academy of Sciences. He received the 1997 Bruning Award of the Federation of Societies for Coatings Technology and the 1999 Godlove Award of the Inter-Society Color Council.

He has been a consultant in color science since 1990. His avocations include photography, astronomy, and playing a 240-stop digital organ he built. His compositions include songs, a string quartet, and a circus march “Clown Alley”, which is played on the calliope at the Barnum and Bailey Circus. He lives in Wappingers Falls, NY, with his wife, Mabel. They have been married 54 years, traveled the world, and have three children and five grandchildren.

Opportunities for NIST/Industry Partnerships
Terry Lynch
Director's Office, Technology Partnerships
National Institute of Standards and Technology

Abstract

NIST has a wide variety of formats available to it in forming mutually beneficial partnerships with industry. These range from informal collaboration to structured Cooperative Research and Development Agreements (CRADAs), from individual researchers working together to large industrial consortia, and from funding programs such as the Advanced Technology and SBIR Programs to contracts for NIST services. This presentation will focus on those mechanisms designed to foster collaborative research (CRADAs, Guest Research Agreements, Memoranda of Understanding) and/or foster use of NIST-developed technology.

Terry Lynch

Terry Lynch is presently the Senior Licensing and CRADA Officer with the National Institute of Standards and Technology, in Gaithersburg, MD where he is involved in licensing NIST technologies, Cooperative Research and Development Agreements, and establishing productive relationships with U.S. He also recently took on the added responsibilities of the NIST SBIR Program Manager. Prior to joining NIST, Mr. Lynch was the Manager for New Business Development for Kobe Steel USA, Inc., implementing Kobe's business development strategy in U.S. in the fields of semiconductor equipment, advanced materials, and electronics, through license agreements, investments, and joint ventures. He held the position of Vice Chairman of Q C Optics Inc., a subsidiary in the semiconductor equipment industry, having structured and implemented the founding of the company. Mr. Lynch also participated in launching of a $20M in-house venture capital fund. He transferred to Kobe from Midrex Corporation, where he had been engaged in international process plant design prior to serving as the Manager of New Ventures. Mr. Lynch began his career as a research engineer for Goodyear Tire and Rubber Company. Mr. Lynch has been actively involved in entrepreneurial organizations, and mentoring start-up companies. He is presently active in the Interagency Technology Transfer Council, Licensing Executives Society, Association of University Technology Managers, and Federal Laboratory Consortium.

NIST-Industry Consortium on Optical Properties of Materials
Leonard Hanssen
Optical Technology Division
National Institute of Standards and Technology

Abstract

The Optical Properties of Materials Consortium was established as a Cooperative and Research Agreement (CRADA) through the Technology Services Office of Industrial Parnerships at NIST. This Consortium was formed to identify critical industrial needs in which NIST should be involved by performing high accuracy optical measurements, developing necessary standards and critically evaluating existing data on the optical properties of materials that are important for the evolving optical industries in the U.S. The optical properties of concern are the reflectance (diffuse & specular), transmittance, emittance, absorptance and the refractive index of mostly bulk materials for the optical radiation from 193nm to 30 micrometers. Optical properties such as Bi-Directional Diffuse Reflectance (BRDF) for materials and the associated development of standards would also be a part of the activity of this Consortium. Representative industries of the Consortium include manufacturers/processors of pharmaceuticals, consumer health products, food and beverages, cosmetics, paper, textiles, chemicals, monochromators, optical filtering/scattering devices, UV, Visible and IR remote sensing instruments, and lasers. The Consortium typically meets at the annual SPIE meeting.

Leonard Hanssen

Leonard Hanssen obtained his Ph. D. in Physics at Cornell University in 1985 studying infrared optical properties of single crystal metal surfaces. Then in the Optical Sciences Division of the Naval Research laboratory, he studied the properties of metal and dielectric thin films, investigated materials and instrumentation for diffuse reflectance, and studied the combustion chemical vapor deposition of diamond. He joined the Radiometric Physics Division at NIST in 1990, where he has worked on the development of high accuracy instrumentation and standard reference materials for infrared optical property measurement.

An Introduction to Measurement of Color of Fluorescent Materials and Fluorescence Standards *Art Springsteen Ph.D.* Avian Technologies, LLC	View Presentation

Abstract
In 1994, the Intersociety Color Council (ISCC) sponsored its annual Williamsburg Conference. The topic that year was the measurement of color and fluorescence. This landmark conference established the state of the art in measurement of fluorescent materials, be they daylight fluorescents, optical brighteners, or security pigments. It is now six years later and the stakes in the matter have changed. There is a much larger demand for accurate color measurement of fluorescent materials and optical brighteners in the paper and textile industries. In addition, safety and security devices widely use luminescent pigments and their quantitation is becoming increasingly important in day to day life. This importance is more than just a theoretical concept- the economic importance is a reality. It has been estimated that in the brightness of paper- dependent on a fluorescent optical brightening agent- a single brightness unit means a difference of Can$150,000,000 to the Canadian economy.
The measurement of color in materials that exhibit fluorescence has long been a problem for industrial users. This paper presents an overview of the theory of fluorescent color, geometry of measurement, the importance of illuminants in determining fluorescent color and the current difficulties in its measurement. Considerations as to why standard spectrophotometers and colorimeters fail to give completely accurate results in measuring such materials will be discussed. An overview of instrumental efforts being developed to perform such measurements with high accuracy will be presented. In addition, the current ‘state of the art’ in standards for fluorescence and fluorescent color will be presented along with suggestions for improvements in artifact standards.
Art Springsteen
Art Springsteen is the president and chief technical officer of Avian Technologies, LLC. Avian Technologies specializes in the design and manufacture of instruments and standards for optical spectometry and other optical radiation measurements. Previous to starting Avian Technologies in 1998, Dr. Springsteen was Principal Scientist and Director for Advanced Development at Labsphere,Inc. for 13 years. During his tenure at Labsphere, he developed over thirty commercial products, including the Spectralon diffuse reflectance material product line, numerous optical coatings, fluorescent materials and accessories for measurement of reflectance, diffuse transmittance and fluorescence. He holds five U.S. patents on materials and instrument design, won a 1990 Photonics Spectra New product of the Year award, and shared another in 1997 for the development of the Labsphere bispectral fluorescence colorimeter.
Dr. Springsteen is the Secretary for the Council for Optical Radiation Measurement, a member of the Board of Directors of the Inter Society Color Council, and a former member of the National Research Council of the U.S. He holds a Ph.D. from West Virginia University in Organic Chemistry, an M.S. in Chemistry from Marshall University and a B.S. in Chemistry from St. Francis College (PA).

Development of New Appearance Measurement Procedures – The ASTM E12.14 Approach
Paul Tannenbaum
The DuPont Company

Abstract

Appearance is the total quality of what we perceive. Color, texture, luster, gloss, haze, sparkle, clarity and roughness are all examples of appearance attributes. The quality of many of our products is judged by combinations of such attributes. Their “appearance value” represents substantial revenues and earnings.

Modern coating and polymer chemistry and application techniques result in surface and sub-surface appearance phenomena which, individually and in combination, defy adequate specification (or characterization) visually and instrumentally. This limits (hinders) our ability to define and consistently reproduce products of desirable quality, or to analyze and exclude unwanted appearance effects. ASTM Committee E12.14 is a new committee desiring to expand basic knowledge in this complex arena and striving to develop visual and instrumental standards based on well founded data.

Classical methods of measuring appearance, i. e. gloss, haze and even color, rely on the disciplines of photometry and radiometry. Within these measurement practices, one detects the LIGHT FLUX subtended by the solid angle defined by the area of the sample being measured and the active area of the detector, such as a photomultiplier tube. Because such measurements are physical in nature and correlate flux variations with surface attributes, they do not measure WHAT WE SEE directly. We must deduce the appearance attribute values via correlative-subjective assessment. Furthermore, the fluxes associated with more than one physical phenomena cannot easily be separated.

Modern imaging equipment, as for instance, line scanners and video cameras, directly IMAGE the item whose appearance attributes are to be judged. With proper attention to lighting and optics, quantitative estimates of these attributes can be determined by powerful optical and image processing algorithms working on clues or features within the image. In this instance proper imaging in conjunction robust calculation can separate the effects of different attributes acting simultaneously.

We will briefly review the classical geometries and equipment used to measure gloss, haze, clarity, distinctness-of-image which form the basis for all current ASTM E12 appearance specifications. Based on this prior art we show by example how more modern imaging equipment can be configured to simultaneously measure: gloss, haze, doi, orange peel and micro-wrinkle for automotive finishes.

Finally, we discuss the current results of an ongoing ASTM E12.14 round robin in which both flux and imaging instrumentation, from many laboratories, have been used to measure the peel, gloss and haze of a de-facto automotive standard for orange peel panels. What is unique about this study is the fact that these panels have also been psychophysically characterized using well-documented techniques by Professor Edgar Chambers III, of Kansas State University. The goal of this study is to determine which measurement methods agree with, and are therefore adequate for the assessment of, visual appearance attributes and where further work is needed. The study will also define where interaction(s) of attributes are significant.

Paul Tannenbaum

Dr. Tannenbaum received a Ph.D. in solid state physics from New York University in 1969. He worked for Bell Telephone Laboratories from 1969 to 1974 doing research in optics and Color Picturephone where he developed his love of color. He joined the Engineering physics Laboratory at DuPont in 1974 and has been there until present working under the mentorship of the late C. D. Reilly on color instrumentation, chromatic adaptation, metamerism indices, and improvements to Kubelka Monk theory. For the past ten years , he has been defining measurement methods for many of the surface appearance attributes of various DuPont products. He is currently Co-Chairman of ASTM Subcommittee E12.14-Mutlidimentional Characterization of Appearance and a volunteer curator at Hagley Museum which presides over the historic ISCC/Hagley color collection.

Characterizing Coating Microstructure *Li-Piin Sung* Building Materials Division National Institute of Standards and Technology	View Presentation

Abstract
The physical measurement of the appearance of a coated object quantifies the physical attributes of the object’s interaction with light. For a pigmented coated object these physical attributes include the light source, the angle of illumination, the viewing angle, and the optical reflectance properties of the coating system resulting from its surface topography and subsurface microstructures. To identify and characterize the determinant microstructure of the coating is crucial for relating the optical reflectance to its related microstructures, and for predicting appearance of a coating from its microstructure, its constituents and changes in appearance that occur as a coating is weathered. A series of samples varying in their microstructural properties (pigment materials, sizes, dispersion, and spatial distribution) were used to investigate the relationship between the nature of the microstructure and the optical reflectance properties of the coatings. The measured microstructures using the laser scanning confocal microscope will be presented and compared to the corresponding optical reflectance data obtained from NIST’s bidirectional reflectance distribution function (BRDF) instruments.
Li-Piin Sung
Li-Piin Sung received a Ph.D. in Physics from the University of California, Santa Barbara, in 1993. She has been at NIST since that time conducting research in polymer physics, neutron scattering, optical scattering. Her current position is a research physicist, in the Organic Building Materials Group, Building Materials Division, at NIST.

An Overview of NIST Measurement Services *Robert Gettings* Standard Reference Materials Program National Institute of Standards and Technology	View Presentation

Abstract
The mission of the Standard Reference Materials Program (SRMP) is to provide reference materials that are the definitive physical sources of measurement traceability in the United States. The Program promotes and supports the development and certification of NIST SRMs essential to industry, academia, and government in order to facilitate commerce and trade and to advance science and technology. This is in support of the NIST mission ‘to strengthen the U.S. economy and improve the quality of life by working with industry to develop and apply technology, measurements and standards.’
SRMP maintains and offers for sale over 1300 different Standard Reference Materials^® (SRMs^®) certified for their chemical composition, chemical properties, or physical properties. SRMs are used for three main purposes: to help develop accurate methods of analysis; to calibrate measurement systems; and to assure the long-term adequacy and integrity of measurement quality assurance programs.
Historically, SRMs have been used as vehicles for transferring measurement science and technology, through channels of industry and commerce, to the nation at large. As such, SRMs are crucial reference points in the establishment of a comprehensive measurement system for the entire nation. This system has met the needs of U.S. industry and commerce for nearly one hundred years and continues to evolve to satisfy more demanding measurement requirements. The current fast pace of technological change coupled with increasing demands on quality, traceability pathways involving SRMs and SRM types, is mandating that new strategies for delivering technology transfer via SRMs be explored and developed.
Each new SRM is the fruit of collaboration between the NIST technical divisions, the NIST Statistical Engineering Division, and SRMP as well as representatives of science and industry. SRMP is the central point at NIST for the coordination and support of all reference material services and related activities. The program provides support to the NIST Laboratory programs in the following areas:
SRM program administration NIST policy implementation related to SRM products and services scientific assessment and independent technical review of SRM data and related documents, market research and SRM needs assessment, reference materials processing and production business services (SRM marketing and sales) information services
Mr. Gettings’ presentation will discuss the SRM certification process and the role SRMP plays in that process.
Robert Gettings
Robert Gettings began his career at NIST as a scientist and engineer investigating the physical and mechanical properties of materials. He received a B.S. in Mechanical Engineering in 1989 and an M.S. in Engineering Materials in 1992, both degrees from the University of Maryland. He joined the NIST Ceramics Division in 1991 to perform pre-standardization research and produce Standard Reference Materials (SRMs) for the ceramics industry.
He transferred to the NIST Standard Reference Materials Program in February 1995. The Program is responsible for producing and distributing over 1300 SRMs in the areas of chemical composition, physical properties and engineering performance for measurement and calibration purposes. Robert serves as Project Manager for approximately 250 SRM projects encompassing the areas of metrology, particle size, hardness, X-ray, and optical properties.
Currently, Robert also manages the sales and marketing efforts of the Standard Reference Materials program including supervising the sales office staff and managing the SRMP website.

Models and Measurements of 3D texture *Kristin J. Dana* Rutgers University	View Presentation

Abstract
This work is an investigation of the visual appearance of real-world surfaces and the dependence of appearance on the geometry of imaging conditions. Image texture can arise not only from surface albedo variations (2D texture) but also from surface height variations (3D texture). Many natural textures fall into the category of 3D texture and yet prior texture research has largely ignored this property. Since the appearance of 3D texture depends on the illumination and viewing direction in a complicated manner, such image texture can be called a bidirectional texture function.
Measurements of BTF (bidirectional texture function) are presented in a database with image textures from over 60 different samples, each observed with over 200 different combinations of viewing and illumination directions. A related quantity to the BTF is the familiar BRDF (bidirectional reflectance distribution function). The measurement methods involved in the BTF database are conducive to a simultaneous measurement of the BRDF. Accordingly, a BRDF database is constructed with reflectance measurements for over 60 different samples, each observed with over 200 different combinations of viewing and illumination directions. The methods involved in collecting each database are described. The reflectance measurement data is fit to recent BRDF models and the resulting parameters are also available in the BRDF database. Both the BRDF and BTF databases are publicly available and have important implications for computer vision and graphics. Recent work in BRDF and BTF modeling is discussed.
Kristin Dana
Kristin Dana completed her PhD degree in August 1999 as a member of the Computer Vision group at Columbia University, advised by Prof. Shree K. Nayar. Before returning to graduate school in 1995, she worked for Sarnoff Corporation in Princeton, NJ (1992-1995). She received a BS in Electrical Engineering from Cooper Union in 1990 and an MS from MIT in 1992. Currently, she is an assistant professor at Rutgers University.

Appearance Engineering: Getting from virtual models to physical designs *Frank Iannarilli, Jr.* Aerodyne Research, Inc.	View Presentation

Abstract
Appearance prediction and appearance engineering both rely on accurate physics-based models of light interaction with scattering properties of 3D object surfaces. Although an object's appearance can be purposefully influenced by configuring its shaping and surface properties, its manifested appearance is also determined by typically ill-controlled variables such as viewpoint and illumination. These points are widely understood. Nevertheless, a point not widely appreciated is that an appearance prediction capability does not equate to an appearance engineering capability; appearance prediction takes the design configuration as a given. Although a design configuration for a singular viewpoint and illumination might be obtained by manual iteration using a prediction framework, such an approach is hopeless for achieving a design that best manifests the desired appearance over a range of viewing situations.
Under aerospace industrial and government sponsorship, Aerodyne has developed a physics-based computer-aided appearance engineering tool, known as "CMO" (for Colorant Mapping Optimizer). Out-of-the-box, it performs 3D materials-based camouflage design. CMO operates using a palette of "colorants" (each possessing full BRDF description), and assigns colorants to a 3D object's surfaces, to optimize various measures of visibility. It solves the problem of determining what fixed coating scheme (if any) achieves given desired appearances under various viewing/illumination situations, using (a) coating selection; and (b) coating placements as its degrees of freedom (for fixed non-dynamic coating scheme).
We delineate and will discuss 3 distinct realms of CMO application: (1) conspicuity minimization (camouflage); (2) conspicuity maximization; and (3) desired appearance-matching. For example, under (2), we envision application to the design of optimal visibility signage, navigation aids, etc. Under (3), we envision application to design of physical material surface schemes to manifest desired appearances (under various viewing/illumination situations). This appears increasingly desired for matching physical packaging to virtual depictions in e-commerce, architectural lighting/coloring, theatrical set design, etc.
Frank J. Iannarilli, Jr.
Mr. Iannarilli is a principal scientist at Aerodyne Research, located near Boston, where he leads the Center for Optical Signature Recognition. His interests are in the areas of signal processing and computational intelligence as applied to optical sensing and discrimination problems.
Before his 10 years at Aerodyne, Mr. Iannarilli spent 5 years at the Air Force Geophysics Lab performing inflight IR measurements and analysis. He has a Masters degree in Electrical Engineering from Brown University and a Bachelor's degree in Physics from the US Air Force Academy.

Optical Measurements and Standard Materials for Color and Appearance *Maria E. Nadal* Optical Technology Division National Institute of Standards and Technology	View Presentation

Abstract
The Optical Technology Division, in conjunction with the Measurement Science for Optical Reflectance and Scattering Project at NIST, is working to establish a laboratory program directed toward the complete characterization of the appearance of surfaces. At present, we are working on several areas of appearance metrology such as establishing a calibration laboratory to provide color standards, a calibration laboratory for specular gloss, developing measurement protocols for gonioapprarent materials, and investigating the relationship between microstructure and appearance properties of surfaces.
In reflectance colorimetry, we are establishing a program to provide calibrated reflectance color standards. Our goal is to provide standards with well-characterized uncertainties that are the smallest possible. We have modeled three sources of uncertainty - the primary standards used to calibrate the reference color instrument, the intrinsic characteristics of the reference instrument, and the properties of the color standards. The final specifications for the reference instrument were decided using our model and a target for the overall color uncertainty of DE^*_ab < 0.5. Details of the uncertainty analysis and the reference reflectance colorimeter will be discussed. The dissemination of NIST measurement capability will consist of a measurement assurance program to help define the sources of uncertainties of commercial instruments, followed by a calibration service.
Reflection gloss is the second most utilized attribute, after color, to evaluate products such as automobiles, textiles, and papers. The NIST reference goniophotometer complies with the standard recommendations for specular gloss at 20°, 60°, and 85° geometries for non-metallic paint samples in the low to high gloss levels described at the ISO 2813 and ASTM D523 standards. In addition, this reference instrument is capable of performing bi-directional reflectance and transmission measurements at angles from 0° to 85° for the incident and viewing angles in compliance with the ASTM E 167 standard. The relative expanded uncertainty (k=2) of the NIST goniophotometer for specular gloss of highly polished black glass is 0.3 % for all three standard geometries. The accuracy of specular gloss measurements depends not only on the properties of the instrument but also to a considerable extent on those of the reference gloss standard. A new primary gloss standard using BaK50 barium crown glass has been developed at NIST. The reference goniophotometer and the new primary standard will be described in this presentation, and provide an accurate calibration facility for specular gloss with the lowest possible uncertainties.
Materials are being manufactured with new and unique appearance attributes, and the traditional measurement techniques are not always capable of adequately characterizing the color attributes or correlating them with visual inspection. Gonioapparent coatings such as metallic and interference pigments exhibit different colors with changes in the illumination or viewing angle, or both. Therefore, the traditional single geometry measurement is not capable of characterized the perceived color variations. Our goal for this project is to determine the set of geometries necessary to accurately characterize the color of interference pigments. Preliminary results will be given in this presentation.
Maria Nadal
Maria Nadal received her Ph.D. in Physical Chemistry from the University of Colorado at Boulder in 1996. In 1997, she joined NIST's efforts in spectrophotometry. Her primary areas of interest are color and appearance and spectral reflectance. She is an active member of ASTM and CIE committees.

The Role of Modeling and Rendering in the NIST Optical Reflectance Project *Fern Hunt* Mathematical and Computational Sciences Division National Institute of Standards and Technology	View Presentation

Abstract
The speaker will begin by discussing NIST's effort to explore the feasibility of using computer rendering as a tool for the design and evaluation of appearance of coated materials. Rendering involves the creation of a synthetic image based on the spatial and spectral distribution of light reflected from surfaces in a scene. Photorealistic images require a reasonably accurate representation of the BRDF of these surfaces. However there is a trade-off between physical realism on the one hand and computational efficiency on the other. The computer graphics community developed a variety of approximations designed to deal with this trade-off but they have developed apart from the optical metrology and modeling community. We describe our attempt at NIST to integrate these approaches. These efforts involve changes in measurement protocol and changes in the rendering software.
Fern Hunt
Fern Hunt obtained her undergraduate degree from Bryn Mawr College and her M.S. and PhD in Mathematics from Courant Institute, New York University. Dr. Hunt has been a mathematician at NIST since 1991. In addition to mathematical research, Hunt has been coordinating the rendering portion of the NIST project on Measurement Science for Optical Reflectance and Scattering.

Phenomenological BRDF Modeling For Engineering Applications *James C. Jafolla and Chris B. Blasband* Surface Optics Corporation	View Presentation

Abstract
This presentation will describe the phenomenological basis for the Scattering Coatings Computer Aided Design (SCATCAD) code. The SCATCAD code predicts the Bidirectional Reflectance Distribution Function (BRDF) and the Hemispherical Directional Reflectance (HDR) of pigmented paint coatings for the purpose of coating design optimization. The code uses techniques for computing the pigment single scattering phase function, multiple scattering radiative transfer, and rough surface scattering to calculate the BRDF and HDR based on the fundamental optical properties of the pigment(s) and binder, pigment number density and size distribution, and surface roughness of the binder interface and substrate. This is a significant enhancement to the two-flux, Kubelka-Munk analysis that has traditionally be used in the coatings industry.
The paper will describe the algorithms used for single scattering from spherical and non-spherical, homogeneous and non-homogeneous pigment particles; the adding/doubling radiative transfer calculations; and the Kirchhoff approximation used in the rough surface analysis. Example calculations and comparison with measurements will be presented.
James Jafolla
Dr. Jafolla is President of Surface Optics Corporation and is working on the design, fabrication, and evaluation of materials for visual and IR signature control. He is developing models for predicting the optical performance of paint coatings, codes for optical constant determination from reflectance and transmittance measurements, and codes for evaluating the resulting platform signature with respect to various threat sensors. In addition, he is involved in developing techniques for multispectral signature suppression. This involves determining coating optical requirements and coating design specifications. The coating designs included pigmented paints, multi-layer stacks, and three-dimensional surface structures.
Previously, Dr. Jafolla worked on projects in a number of areas including the analytical prediction of the bidirectional reflectance of paint coatings, RCS predictions from complex shapes, IR signature prediction, radiative transfer through cloudy atmospheres, and sensor performance evaluation models. He is the principle author of the Coatings Reflectance Engineering Evaluation Program (CREEP) and the Surveillance Systems Evaluation Model (SURSEM). Currently Dr. Jafolla is involved in the development and validation of the Scattering Coatings Computer Aided Design (ScatCad) tool for advanced design and evaluation of signature control materials and surfaces.

Modeling and Measurements for Light Scattering from Smooth Surfaces *Thomas A. Germer* Optical Technology Division National Institute of Standards and Technology	View Presentation

Abstract
While calculations of light scattered by arbitrarily rough surfaces can be extremely difficult, the smooth surface limit can be handled readily using vector perturbation theory. A unique feature of the theory is that terms determining the intensity of the scattered light are separable from those determining the polarization. That is, the polarization of the light has a unique signature, which indicates that a surface scatters due to roughness. This finding, together with its experimental verification, has given rise to a new light scattering technique, coined bidirectional ellipsometry, which allows the scattering from surface roughness to be separated from other sources of scatter. In this talk, examples will be given, demonstrating the applicability of the technique to the inspection or characterization of semiconductor wafers, optics, thin films, and paints.
Thomas Germer
Thom Germer received his undergraduate and graduate training at U.C. Berkeley and Cornell University, respectively. From 1992 through 1994, he held a NRC Postdoctoral Research Fellowship at NIST. In 1995, he joined NIST's efforts in optical scattering.

Predicting Optical Properties of Synthetic Fibers
Barry Rubin
The DuPont Company

Abstract

The cross-sectional size and shape of the individual fibers in a synthetic yarn bundle play a major role in determining their optical properties and, in turn, the appearance attributes of the carpet or fabric made from the yarn. These attributes include color due to dye in the fibers and glitter, or small flashes of light. A computer optical ray trace model has been developed to improve the fundamental understanding of the interaction of light with fiber geometry and to guide the design of new fiber products for specific end uses. An outline of the model and examples of its application are presented.

Barry Rubin

Barry Rubin received a Ph.D. in Physics from the Pennsylvania State University in1980. His research area was experimental high-resolution molecular spectroscopy. In 1980, he joined Engineering Research at DuPont where he has been working in applied optics, image analysis and the measurement and modeling of appearance.

Surface Characterization and Modeling for Coatings *Egon Marx* Precision Engineering Division National Institute of Standards and Technology	View Presentation

Abstract
The surface of a number of epoxy coatings of varying roughness were measured using interferometric microscopy to obtain the data on the surface topography that is used as input to light scattering calculations. These calculations were carried out using two computer codes, one based on the Kirchhoff approximation for the scalar wave equation and the other based on the reflection of light rays by locally flat surfaces. It is assumed that the scattering is a surface effect and that a good approximation to the angular distribution of scattered light is obtained in the formulation for a perfect conductor. The angular distribution of the scattered light calculated by the Kirchhoff approximation has to be convolved with the measured instrument response to compare with measured intensity distributions. The ray reflection code uses the aperture of the detector in the computation to simulate the instrument. The results obtained with these different methods are comparable to those measured by the instrument.
Egon Marx
Egon Marx was born in Cologne, Germany, on April 4, 1937. He received the E. E. degree from the University of Chile, Santiago, Chile, in 1959, and the Ph. D. degree in physics from the California Institute of Technology, Pasadena, in 1963.
He has taught graduate and undergraduate courses in physics at the University of Chile, Clarkson University, and Drexel University, while doing research in the theory of classical and quantum fields and in relativistic quantum mechanics. In 1972, he joined the Harry Diamond Laboratories, where he worked on the effects of electromagnetic pulses and in computer simulation of communications systems. Since 1980 he has been working at the National Institute of Standards and Technology doing research in the theory and numerical applications of electromagnetic scattering and Monte Carlo simulation of electrons in electron microscopes, while continuing with his work in relativistic quantum mechanics and the theory of elementary particles.

Interactive Realism with Multi-Pass Rendering *Marc Olano* Silicon Graphics, Inc.	View Presentation
	(HTML)
Abstract
Graphics hardware systems use simplified appearance models and approximations to achieve interactivity. These simple models are sufficient for some purposes, but are not intended to give an accurate representation of real surfaces. For applications where both interactivity and reproduction or prediction of real object appearance are important, we can combine several simple rendering passes to get a more complex and accurate result. In this talk, I will present some examples as well as some general methods used when converting an appearance model into multiple rendering passes.
Marc Olano
Marc Olano is currently at SGI, where he is investigating advanced appearance modeling and shading techniques for current and future graphics hardware. Olano received his Ph.D. in computer science from the University of North Carolina in Chapel Hill for investigation of a shading language for the PixelFlow graphics system. He has also done work on rendering algorithms, model simplification and scientific visualization.

An Appearance Based Rendering System *Gary Meyer* University of Oregon	View Presentation
	(PowerPoint Show)
Abstract
A public domain realistic imaging system is being developed for use in the appearance and coatings industry. The system is built upon the Radiance rendering program and it incorporates an efficient Monte Carlo technique for evaluating arbitrary bidirectional reflection distribution functions (BRDF's). This rendering system has been used with data from a spectragoniophotometer to make pictures of metallic automotive finishes, and it has been employed to synthesize images from an analytic model of surface reflection that was developed by NIST. The realistic imaging system also incorporates a new reflection model that utilizes standard appearance measurements that are common within the coatings industry. These measurements include gloss, haze, distinctness of image, and the three angular measurements that characterize the flop or travel of a metallic paint.
Gary Meyer
Gary Meyer is an associate professor in the Department of Computer and Information Science at the University of Oregon. His research interests include the synthesis of color in computer graphic pictures, perceptual issues related to synthetic image generation, and color reproduction and color selection for the human-computer interface. Meyer has been a member of the technical staff at Bell Telephone Laboratories. He has received a BS from the University of Michigan, an MS from Stanford University, and a PhD from Cornell University. He is a member of ACM SIGGRAPH, IEEE Computer Society, SID, ISCC, and SPIE.

Computer Rendering of Anisotropic Surfaces *Jos Stam* Alias \| Wavefront	View Presentation

Abstract
The reflection of light from surfaces is a fundamental problem in computer graphics. Although many reflection models have been proposed, few take into account the wave nature of light. In this talk, I will derive a new class of reflection models for metallic surfaces that handle the effects of diffraction. Diffraction is a purely wave-like phenomenon and cannot be properly modeled using the ray theory of light alone. A common example of a surface which exhibits diffraction is the compact disk. A characteristic of such surfaces is that they reflect light in a very colorful manner. Our model is also a generalization of most reflection models encountered in computer graphics. In particular, we extend the He-Torrance model to handle anisotropic reflections. This is achieved by rederiving, in a more general setting, results from surface wave physics which were taken for granted by other researchers. Specifically, our use of Fourier analysis has enabled us to tackle the difficult task of analytically computing the Kirchhoff integral of surface scattering.
Jos Stam
Jos Stam is currently a research scientist at Alias\|Wavefront. He was born in The Netherlands and educated in Geneva, Switzerland. He holds B.S. degrees in Computer Science (1988) and Pure Mathematics (1989) from the University of Geneva and received his Master's (1991) and Ph.D. (1995) degrees in Computer Science from the University of Toronto. From 1995 to 1997 he did research at INRIA in France and at the National Research Center (VTT) in Finland as an ERCIM postdoctoral fellow. He joined Alias\|wavefront's Seattle office in June 1997

Appearance Issues for Electronic Commerce *Holly Rushmeier* IBM T J Watson Research	View Presentation

Abstract
As the capabilities of networks and home computers increase, it is being coming possible to incorporate three dimensional computer graphics into e-commerce applications. A number of retail sites have already been developed that allow shoppers to view three dimensional versions of objects they wish to buy.
Many issues need to be addressed to make product inspection in e-retail useful though, beyond just the bandwidth to make it easy to download objects. There are issues on both the server and client sides.
On the server end, inexpensive systems are needed to capture the objects. While cheap scanners are available, almost all capture color by simply capturing a single image. Inexpensive scanners are needed that capture at least some spectral and directional characteristics of objects so they can be correctly displayed for the user. Without the ability to appropriately relight and reposition an object, three dimensional objects offer little (or possibly less) than a high quality two dimensional color images.
Besides being inexpensive, scanning systems for electronic commerce also need to be easy to use. Small retailers or manufacturers can not afford to hire a technician to run a system. The hardware systems must be robust, and the software should make minimal demands on the operator.
On the client side, work is needed to make the manipulation of three-dimensional objects more intuitive. Most graphics systems have been developed for technical users. A much more diverse population needs to be considered for home applications. Accurate presentation of tone and color is also needed. This may be extremely difficult on the many possible CRT and flat panel devices in use. Some simple method of letting home users "self-calibrate" is needed.
We will present our recent work on developing inexpensive, electronic camera-based systems for capturing shape and surface appearance. We combine an off-the-shelf shape scanner with a custom photometric lighting system. We will also discuss new ideas for interactive viewers. Our scanner/viewing technologies were originally developed for scanning Michelangelo's Florentine Pieta` (http://www.research.ibm.com/pieta) and we are now shifting our emphasis to e-commerce applications.
Holly Rushmeier
Holly Rushmeier received the BS, MS and PhD degrees in mechanical engineering from Cornell University in 1977, 1986 and 1988 respectively. She is a research staff member at the IBM T.J. Watson Research Center. Since receiving the PhD, she has held positions at the Georgia Institute of Technology and the National Institute of Standards and Technology. In 1990, she was selected as a US National Science Foundation Presidential Young Investigator. In 1996 she served as the papers chair for the ACM SIGGRAPH conference, in 1998 as the papers co-chair for the IEEE Visualization conference. From 1997 to 1999 she was Editor-in-Chief of ACM Transactions on Graphics. Her research interests include data visualization, rendering algorithms, and acquisition of input data for computer graphics image synthesis.

Measurement Science for Optical Reflectance and Scattering

Workshop on Metrology and Modeling of Color and Appearance -- Workshop Presentations