A photographer is a person who makes photographs. As in other arts, the definitions of amateur and professional are not categorical. An amateur photographer takes snapshots for pleasure to remember events, places or friends with no intention of selling the images to others. A professional photographer is to take photographs for a session and image purchase fee, by salary or through the display, resale or use of those photographs. A professional photographer may be an employee, for example of a newspaper, or may contract to cover a particular planned event such as a wedding or graduation, or to illustrate an advertisement. Others, like fine art photographers, are freelancers, first making an image and licensing or making printed copies of it for sale or display; some workers, such as crime scene photographers, estate agents and scientists, make photographs as part of other work. Photographers who produce moving rather than still pictures are called cinematographers, videographers or camera operators, depending on the commercial context.
The term professional may imply preparation, for example, by academic study or apprenticeship by the photographer in pursuit of photographic skills. A hallmark of a professional is that they invest in continuing education through associations. Many associations offer the opportunity to test and exhibit acumen in order to attain credentials such as Certified Professional Photographer or Master Photographer. While there is no compulsory registration requirement for professional photographer status, operating a business requires having a business license in most cities and counties. Having commercial insurance is required by most venues if photographing a wedding or a public event. Photographers who operate a legitimate business can provide these items. Photographers can be categorized based on the subjects; some photographers explore subjects typical of paintings such as landscape, still life, portraiture. Other photographers specialize in subjects unique to photography, including street photography, documentary photography, fashion photography, wedding photography, war photography, aviation photography and commercial photography.
It is worth noting that the type of work commissioned will have pricing associated with the image's usage. The exclusive right of photographers to copy and use their products is protected by copyright. Countless industries purchase photographs on products; the photographs seen on magazine covers, in television advertising, on greeting cards or calendars, on websites, or on products and packages, have been purchased for this use, either directly from the photographer or through an agency that represents the photographer. A photographer uses a contract to sell the "license" or use of his or her photograph with exact controls regarding how the photograph will be used, in what territory it will be used, for which products; this is referred to as usage fee and is used to distinguish from production fees. An additional contract and royalty would apply for each additional use of the photograph; the contract may be for other duration. The photographer charges a royalty as well as a one-time fee, depending on the terms of the contract.
The contract may be for exclusive use of the photograph. The contract can stipulate that the photographer is entitled to audit the company for determination of royalty payments. Royalties vary depending on the industry buying the photograph and the use, for example, royalties for a photograph used on a poster or in television advertising may be higher than for use on a limited run of brochures. A royalty is often based on the size at which the photo will be used in a magazine or book, cover photos command higher fees than photos used elsewhere in a book or magazine. Photos taken by a photographer while working on assignment are work for hire belonging to the company or publication unless stipulated otherwise by contract. Professional portrait and wedding photographers stipulate by contract that they retain the copyright of their photos, so that only they can sell further prints of the photographs to the consumer, rather than the customer reproducing the photos by other means. If the customer wishes to be able to reproduce the photos themselves, they may discuss an alternative contract with the photographer in advance before the pictures are taken, in which a larger up front fee may be paid in exchange for reprint rights passing to the customer.
There are major companies who have maintained catalogues of stock photography and images for decades, such as Getty Images and others. Since the turn of the 21st century many online stock photography catalogues have appeared that invite photographers to sell their photos online and but for little money, without a royalty, without control over the use of the photo, the market it will be used in, the products it will be used on, time duration, etc. Commercial photographers may promote their work to advertising and editorial art buyers via printed and online marketing vehicles. Many people upload their photographs to social networking websites and other websites, in order to share them with a particular group or with the general public; those interested in legal precision may expl
Museum of Modern Art
The Museum of Modern Art is an art museum located in Midtown Manhattan, New York City, on 53rd Street between Fifth and Sixth Avenues. MoMA plays a major role in developing and collecting modernist art, is identified as one of the largest and most influential museums of modern art in the world. MoMA's collection offers an overview of modern and contemporary art, including works of architecture and design, painting, photography, illustrated books and artist's books and electronic media; the MoMA Library includes 300,000 books and exhibition catalogs, over 1,000 periodical titles, over 40,000 files of ephemera about individual artists and groups. The archives holds primary source material related to the history of contemporary art; the idea for the Museum of Modern Art was developed in 1929 by Abby Aldrich Rockefeller and two of her friends, Lillie P. Bliss and Mary Quinn Sullivan, they became known variously as "the Ladies", "the daring ladies" and "the adamantine ladies". They rented modest quarters for the new museum in the Heckscher Building at 730 Fifth Avenue in Manhattan, it opened to the public on November 7, 1929, nine days after the Wall Street Crash.
Abby had invited A. Conger Goodyear, the former president of the board of trustees of the Albright Art Gallery in Buffalo, New York, to become president of the new museum. Abby became treasurer. At the time, it was America's premier museum devoted to modern art, the first of its kind in Manhattan to exhibit European modernism. One of Abby's early recruits for the museum staff was the noted Japanese-American photographer Soichi Sunami, who served the museum as its official documentary photographer from 1930 until 1968. Goodyear enlisted Paul J. Frank Crowninshield to join him as founding trustees. Sachs, the associate director and curator of prints and drawings at the Fogg Museum at Harvard University, was referred to in those days as a collector of curators. Goodyear asked him to recommend a director and Sachs suggested Alfred H. Barr, Jr. a promising young protege. Under Barr's guidance, the museum's holdings expanded from an initial gift of eight prints and one drawing, its first successful loan exhibition was in November 1929, displaying paintings by Van Gogh, Gauguin, Cézanne, Seurat.
First housed in six rooms of galleries and offices on the twelfth floor of Manhattan's Heckscher Building, on the corner of Fifth Avenue and 57th Street, the museum moved into three more temporary locations within the next ten years. Abby's husband was adamantly opposed to the museum and refused to release funds for the venture, which had to be obtained from other sources and resulted in the frequent shifts of location, he donated the land for the current site of the museum, plus other gifts over time, thus became in effect one of its greatest benefactors. During that time it initiated many more exhibitions of noted artists, such as the lone Vincent van Gogh exhibition on November 4, 1935. Containing an unprecedented sixty-six oils and fifty drawings from the Netherlands, as well as poignant excerpts from the artist's letters, it was a major public success due to Barr's arrangement of the exhibit, became "a precursor to the hold van Gogh has to this day on the contemporary imagination"; the museum gained international prominence with the hugely successful and now famous Picasso retrospective of 1939–40, held in conjunction with the Art Institute of Chicago.
In its range of presented works, it represented a significant reinterpretation of Picasso for future art scholars and historians. This was wholly masterminded by Barr, a Picasso enthusiast, the exhibition lionized Picasso as the greatest artist of the time, setting the model for all the museum's retrospectives that were to follow. Boy Leading a Horse was contested over ownership with the Solomon R. Guggenheim Museum. In 1941, MoMA hosted the ground-breaking exhibition, Indian Art of the United States, that changed the way American Indian arts were viewed by the public and exhibited in art museums; when Abby Rockefeller's son Nelson was selected by the board of trustees to become its flamboyant president in 1939, at the age of thirty, he became the prime instigator and funder of its publicity and subsequent expansion into new headquarters on 53rd Street. His brother, David Rockefeller joined the museum's board of trustees in 1948 and took over the presidency when Nelson was elected Governor of New York in 1958.
David subsequently employed the noted architect Philip Johnson to redesign the museum garden and name it in honor of his mother, the Abby Aldrich Rockefeller Sculpture Garden. He and the Rockefeller family in general have retained a close association with the museum throughout its history, with the Rockefeller Brothers Fund funding the institution since 1947. Both David Rockefeller, Jr. and Sharon Percy Rockefeller sit on the board of trustees. In 1937, MoMA had shifted to offices and basement galleries in the Time-Life Building in Rockefeller Center, its permanent and current home, now renovated, designed in the International Style by the modernist architects Philip L. Goodwin and Edward Durell Stone, opened to the public on May 10, 1939, attended by an illustrious company of 6,000 people, with an opening address via radio from the White House by President Franklin D. Roosevelt. On April 15, 1958, a fire on the second floor destroyed an 18 foot long Monet Water Lilies painting (the current Mone
Cray Inc. is an American supercomputer manufacturer headquartered in Seattle, Washington. It manufactures systems for data storage and analytics. Several Cray supercomputer systems are listed in the TOP500, which ranks the most powerful supercomputers in the world. Cray manufactures its products in Chippewa Falls, where its founder, Seymour Cray, was born and raised; the company has offices in Bloomington and numerous other sales, engineering, R&D locations around the world. The company's predecessor, Cray Research, Inc. was founded in 1972 by computer designer Seymour Cray. Seymour Cray went on to form the spin-off Cray Computer Corporation, in 1989, which went bankrupt in 1995, while Cray Research was bought by SGI the next year. Cray Inc. was formed in 2000 when Tera Computer Company purchased the Cray Research Inc. business from SGI and adopted the name of its acquisition. Seymour Cray began working in the computing field in 1950 when he joined Engineering Research Associates in Saint Paul, Minnesota.
There, he helped to create the ERA 1103. ERA became part of UNIVAC, began to be phased out, he left the company in 1960. He worked out of the CDC headquarters in Minneapolis, but grew upset by constant interruptions by managers, he set up a lab at his home town in Chippewa Falls, about 85 miles to the east. Cray had a string of successes at CDC, including the CDC 6600 and CDC 7600; when CDC ran into financial difficulties in the late 1960s, development funds for Cray's follow-on CDC 8600 became scarce. When he was told the project would have to be put "on hold" in 1972, Cray left to form his own company, Cray Research Inc. Copying the previous arrangement, Cray kept the research and development facilities in Chippewa Falls, put the business headquarters in Minneapolis; the company's first product, the Cray-1 supercomputer, was a major success because it was faster than all other computers at the time. The first system was sold within a month for US$8.8 million. Seymour Cray continued working, this time on the Cray-2, though it only ended up being marginally faster than the Cray X-MP, developed by another team at the company.
Cray soon left the CEO position to become an independent contractor. He started a new VLSI technology lab for the Cray-2 in Boulder, Cray Laboratories, in 1979, which closed in 1982. However, the changing political climate resulted in poor sales prospects. Only one Cray-3 was delivered, a number of follow-on designs were never completed; the company filed for bankruptcy in 1995. CCC's remains began Cray's final corporation, SRC Computers, Inc. Cray Research continued development along a separate line of computers with lead designer Steve Chen and the Cray X-MP. After Chen's departure, the Cray Y-MP, Cray C90 and Cray T90 were developed on the original Cray-1 architecture but achieved much greater performance via multiple additional processors, faster clocks, wider vector pipes; the uncertainty of the Cray-2 project gave rise to a number of Cray-object-code compatible "Crayette" firms: Scientific Computer Systems, American Supercomputer and one other firm. These firms did not mean to compete against Cray and therefore attempted less expensive, slower CMOS versions of the X-MP with the release of the COS operating system and the CFT Fortran compiler.
A series of massively parallel computers from Thinking Machines, Kendall Square Research, Intel Supercomputing Systems Division, nCUBE, MasPar and Meiko Scientific took over the 1980s high performance market. At first, Cray Research denigrated such approaches by complaining that developing software to use the machines was difficult – a true complaint in the era of the ILLIAC IV, but becoming less so each day. Cray realized that the approach was the only way forward and started a five-year project to capture the lead in this area: the plan's result was the DEC Alpha-based Cray T3D and Cray T3E series, which left Cray as the only remaining supercomputer vendor in the market besides NEC by 2000. Most sites with a Cray installation were considered a member of the "exclusive club" of Cray operators. Cray computers were considered quite prestigious because Crays were expensive machines, the number of units sold was small compared to ordinary mainframes; this perception extended to countries as well: to boost the perception of exclusivity, Cray Research's marketing department had promotional neckties made with a mosaic of tiny national flags illustrating the "club of Cray-operating countries".
New vendors introduced small supercomputers, known as minisupercomputers during the late 1980s and early 1990s, which out-competed low-end Cray machines in the market. The Convex Computer series, as well as a number of small-scale parallel machines from companies like Pyramid Technology and Alliant Computer Systems were popular. One such vendor was Supertek, whose S-1 machine was an air-cooled CMOS implementation of the X-MP processor. Cray purchased Supertek in 1990 and sold the S-1 as the Cray XMS, but the machine proved problematic.
Garry Winogrand was an American street photographer from the Bronx, New York, known for his portrayal of U. S. life and its social issues, in the mid-20th century. Though he photographed in Los Angeles and elsewhere, Winogrand was a New York photographer, he received three Guggenheim Fellowships to work on personal projects, a fellowship from the National Endowment for the Arts, published four books during his lifetime. He was one of three photographers featured in the influential New Documents exhibition at Museum of Modern Art in New York in 1967 and had solo exhibitions there in 1969, 1977, 1988, he supported himself by working as a freelance photojournalist and advertising photographer in the 1950s and 1960s, taught photography in the 1970s. His photographs featured in photography magazines including Popular Photography, Contemporary Photographer, Photography Annual. Photography curator and critic John Szarkowski called Winogrand the central photographer of his generation. Critic Sean O'Hagan, writing in The Guardian in 2014, said "In the 1960s and 70s, he defined street photography as an attitude as well as a style – and it has laboured in his shadow since, so definitive are his photographs of New York."
Phil Coomes, writing for BBC News in 2013, said "For those of us interested in street photography there are a few names that stand out and one of those is Garry Winogrand, whose pictures of New York in the 1960s are a photographic lesson in every frame."At the time of his death Winogrand's late work remained undeveloped, with about 2,500 rolls of undeveloped film, 6,500 rolls of developed but not proofed exposures, about 3,000 rolls only realized as far as contact sheets being made. Winogrand's parents and Bertha, emigrated to the US from Budapest and Warsaw. Garry grew up with his sister Stella in a predominantly Jewish working-class area of the Bronx, New York, where his father was a leather worker in the garment industry, his mother made neckties for piecemeal work. Winogrand entered the US Army Air Force, he returned to New York in 1947 and studied painting at City College of New York and painting and photography at Columbia University in New York, in 1948. He attended a photojournalism class taught by Alexey Brodovitch at The New School for Social Research in New York in 1951.
Winogrand married Adrienne Lubeau in 1952. They had two children, Laurie in 1956 and Ethan in 1958, they separated in 1963 and divorced in 1966. He worked as a freelance advertising photographer in the 1950s and 1960s. Between 1952 and 1954 he freelanced with the PIX Publishing agency in Manhattan on an introduction from Ed Feingersh, from 1954 at Brackman Associates. Two of Winogrand's photographs appeared in the 1955 The Family of Man exhibition at the Museum of Modern Art in New York, his first solo show was held at Image Gallery in New York in 1959. His first notable exhibition was in Five Unrelated Photographers in 1963 at MoMA in New York, along with Minor White, George Krause, Jerome Liebling, Ken Heyman. In the 1960s, he photographed in New York City at the same time as contemporaries Lee Friedlander and Diane Arbus. In 1964 Winogrand was awarded a Guggenheim Fellowship from the John Simon Guggenheim Memorial Foundation to travel "for photographic studies of American life". In 1966 he exhibited at the George Eastman House in Rochester, New York with Friedlander, Duane Michals, Bruce Davidson, Danny Lyon in an exhibition entitled Toward a Social Landscape, curated by Nathan Lyons.
In 1967 his work was included in the "influential" New Documents show at MoMA in New York with Diane Arbus and Lee Friedlander, curated by John Szarkowski. Around 1967 Winogrand married Judy Teller, they were together until 1969. His photographs of the Bronx Zoo and the Coney Island Aquarium made up his first book The Animals, a collection of pictures that observes the connections between humans and animals, he was awarded his second Guggenheim Fellowship in 1969 to continue exploring "the effect of the media on events", through the novel phenomenon of events created for the mass media. Between 1969 and 1976 he photographed at public events, producing 6,500 prints for Papageorge to select for his solo exhibition at MoMA, book, Public Relations. In 1972 he married Eileen Adele Hale, with whom he had Melissa, he supported himself in the 1970s by teaching, first in New York. He moved to Chicago in 1971 and taught photography at the Institute of Design, Illinois Institute of Technology between 1971 and 1972.
He moved to Texas in 1973 and taught at the University of Texas at Austin between 1973 and 1978. He moved to Los Angeles in 1978. In 1979 he used his third Guggenheim Fellowship to travel throughout the southern and western United States investigating the social issues of his time. In his book Stock Photographs he showed "people in relation to each other and to their show animals" at the Fort Worth Fat Stock Show and Rodeo. Szarkowski, the Director of Photography at New York's MoMA, became an editor and reviewer of Winogrand's work. Szarkowski called him the central photographer of his generation. Winogrand was diagnosed with gallbladder cancer on 1 February 1984 and went to the Gerson Clinic in Tijuana, Mexico, to seek an alternative cure, he died on 19 March, at age 56. At the time of his death his late work remained unprocessed, with about 2,500 rolls of undeveloped film, 6,500 rolls of developed but not proofed exposures, about 3,000 rolls only realized as far as contact sheets being made.
In total he left nearly 300,000 unedited images. The Garry Winogrand Archive at the Center for
Christie's is a British auction house. It was founded in 1766 by James Christie, its main premises are on King Street, St James's, in London and in the Rockefeller Center in New York City. The company is owned by the holding company of François-Henri Pinault. Sales in 2015 totalled £4.8 billion. In 2017 the Salvator Mundi was sold for $450.3 million at Christie's, which at that time was the highest price paid for a single painting at an auction. The official company literature states that founder James Christie conducted the first sale in London, England, on 5 December 1766, the earliest auction catalogue the company retains is from December 1766. However, other sources note that James Christie rented auction rooms from 1762, newspaper advertisements for Christie's sales dating from 1759 have been traced. Christie's was a public company, listed on the London Stock Exchange, from 1973 to 1999. In 1974, Jo Floyd was appointed chairman of Christie's, he served as chairman of Christie's International plc from 1976 to 1988, until handing over to Lord Carrington, was a non-executive director until 1992.
Christie's International Inc. held its first sale in the United States in 1977. Christie's growth was steady since 1989, when it had 42 % of the auction market. In 1990, the company reversed a long-standing policy and guaranteed a minimum price for a collection of artworks in its May auctions. In 1996, sales exceeded those of Sotheby's for the first time since 1954. However, profits did not grow at the same pace. In 1993, Christie's paid $12.7 million for the London gallery Spink & Son, which specialised in Oriental art and British paintings. The company bought Leger Gallery for $3.3 million in 1996, merged it with Spink to become Spink-Leger. Spink-Leger closed in 2002. To make itself competitive with Sotheby's in the property market, Christie's bought Great Estates in 1995 the largest network of independent estate agents in North America, changing its name to Christie's Great Estates Inc. In December 1997, under the chairmanship of Lord Hindlip, Christie's put itself on the auction block, but after two months of negotiations with the consortium-led investment firm SBC Warburg Dillon Read it did not attract a bid high enough to accept.
In May 1998, François Pinault's holding company, Groupe Artémis S. A. first bought 29.1 percent of the company for $243.2 million, subsequently purchased the rest of it in a deal that valued the entire company at $1.2 billion. The company has since not been reporting profits, its policy, in line with UK accounting standards, is to convert non-UK results using an average exchange rate weighted daily by sales throughout the year. In 2002, Christie's France held its first auction in Paris. Like Sotheby's, Christie's became involved in high-profile private transactions. In 2006, Christie's offered a reported $21 million guarantee to the Donald Judd Foundation and displayed the artist's works for five weeks in an exhibition that won an AICA award for "Best Installation in an Alternative Space". In 2007 it brokered a $68 million deal that transferred Thomas Eakins's The Gross Clinic from the Jefferson Medical College at the Thomas Jefferson University in Philadelphia to joint ownership by the Philadelphia Museum of Art and the Pennsylvania Academy of the Fine Arts.
In the same year, the Haunch of Venison gallery became a subsidiary of the company. On 28 December 2008, The Sunday Times reported that Pinault's debts left him "considering" the sale of Christie's and that a number of "private equity groups" were thought to be interested in its acquisition. In January 2009, the company employed 2,100 people worldwide, though an unspecified number of staff and consultants were soon to be cut due to a worldwide downturn in the art market. With sales for premier Impressionist and contemporary artworks tallying only US$248.8 million in comparison to US$739 million just a year before, a second round of job cuts began after May 2009. Guy Bennett resigned just before to the beginning of the summer 2009 sales season. Although the economic downturn has encouraged some collectors to sell art, others are unwilling to sell in a market which may yield only bargain prices. On 1 January 2017, Guillaume Cerutti was appointed chief executive officer. Patricia Barbizet was appointed chief executive officer of Christie's in 2014, the first female CEO of the company.
She replaced Steven Murphy, hired in 2010 to develop their online presence and launch in new markets, such as China. In 2012, Impressionist works, which dominated the market during the 1980s boom, were replaced by contemporary art as Christie's top category. Asian art was the third most-lucrative area. With income from classic auctioneering falling, treaty sales made £413.4 million in the first half of 2012, an increase of 53% on the same period last year. The company has promoted curated events, centred on a theme rather than an art classification or time period; as part of a companywide review in 2017, Christie's announced the layoffs of 250 employees, or 12 percent of the total work force, based in Britain and Europe. From 2008 until 2013, Christie's charged 25 percent for the first $50,000. From 2013, it charged 25 percent for the first $75,000. Christie's main London salesroom is on
Jazz is a music genre that originated in the African-American communities of New Orleans, United States, in the late 19th and early 20th centuries, developed from roots in blues and ragtime. Jazz is seen by many as "America's classical music". Since the 1920s Jazz Age, jazz has become recognized as a major form of musical expression, it emerged in the form of independent traditional and popular musical styles, all linked by the common bonds of African-American and European-American musical parentage with a performance orientation. Jazz is characterized by swing and blue notes and response vocals and improvisation. Jazz has roots in West African cultural and musical expression, in African-American music traditions including blues and ragtime, as well as European military band music. Intellectuals around the world have hailed jazz as "one of America's original art forms"; as jazz spread around the world, it drew on national and local musical cultures, which gave rise to different styles. New Orleans jazz began in the early 1910s, combining earlier brass-band marches, French quadrilles, biguine and blues with collective polyphonic improvisation.
In the 1930s arranged dance-oriented swing big bands, Kansas City jazz, a hard-swinging, improvisational style and Gypsy jazz were the prominent styles. Bebop emerged in the 1940s, shifting jazz from danceable popular music toward a more challenging "musician's music", played at faster tempos and used more chord-based improvisation. Cool jazz developed near the end of the 1940s, introducing calmer, smoother sounds and long, linear melodic lines; the 1950s saw the emergence of free jazz, which explored playing without regular meter and formal structures, in the mid-1950s, hard bop emerged, which introduced influences from rhythm and blues and blues in the saxophone and piano playing. Modal jazz developed in the late 1950s, using the mode, or musical scale, as the basis of musical structure and improvisation. Jazz-rock fusion appeared in the late 1960s and early 1970s, combining jazz improvisation with rock music's rhythms, electric instruments, amplified stage sound. In the early 1980s, a commercial form of jazz fusion called smooth jazz became successful, garnering significant radio airplay.
Other styles and genres abound in the 2000s, such as Afro-Cuban jazz. The origin of the word "jazz" has resulted in considerable research, its history is well documented, it is believed to be related to "jasm", a slang term dating back to 1860 meaning "pep, energy". The earliest written record of the word is in a 1912 article in the Los Angeles Times in which a minor league baseball pitcher described a pitch which he called a "jazz ball" "because it wobbles and you can't do anything with it"; the use of the word in a musical context was documented as early as 1915 in the Chicago Daily Tribune. Its first documented use in a musical context in New Orleans was in a November 14, 1916 Times-Picayune article about "jas bands". In an interview with NPR, musician Eubie Blake offered his recollections of the slang connotations of the term, saying, "When Broadway picked it up, they called it'J-A-Z-Z', it wasn't called that. It was spelled'J-A-S-S'; that was dirty, if you knew what it was, you wouldn't say it in front of ladies."
The American Dialect Society named it the Word of the Twentieth Century. Jazz is difficult to define because it encompasses a wide range of music spanning a period of over 100 years, from ragtime to the rock-infused fusion. Attempts have been made to define jazz from the perspective of other musical traditions, such as European music history or African music, but critic Joachim-Ernst Berendt argues that its terms of reference and its definition should be broader, defining jazz as a "form of art music which originated in the United States through the confrontation of the Negro with European music" and arguing that it differs from European music in that jazz has a "special relationship to time defined as'swing'". Jazz involves "a spontaneity and vitality of musical production in which improvisation plays a role" and contains a "sonority and manner of phrasing which mirror the individuality of the performing jazz musician". In the opinion of Robert Christgau, "most of us would say that inventing meaning while letting loose is the essence and promise of jazz".
A broader definition that encompasses different eras of jazz has been proposed by Travis Jackson: "it is music that includes qualities such as swing, group interaction, developing an'individual voice', being open to different musical possibilities". Krin Gibbard argued that "jazz is a construct" which designates "a number of musics with enough in common to be understood as part of a coherent tradition". In contrast to commentators who have argued for excluding types of jazz, musicians are sometimes reluctant to define the music they play. Duke Ellington, one of jazz's most famous figures, said, "It's all music." Although jazz is considered difficult to define, in part because it contains many subgenres, improvisation is one of its defining elements. The centrality of improvisation is attributed to the influence of earlier forms of music such as blues, a form of folk music which arose in part from the work songs and field hollers of African-American slaves on plantations; these work songs were structured around a repetitive call-and-response pattern, but early blues was improvisational.
Classical music performance is evaluated more by its fidelity to the musical score, with less attention given to interpretation and accompaniment. The classical performer's goal is to play the composition. In contrast, jazz is characterized by the product of i