William A. Thornton, Jr.

OBITUARY FOR THE GENERAL PUBLIC

William A. Thornton, Jr., 82.  1979 U.S. National ‘Inventor of the Year’, Discovered the ‘Prime Colors’ of Human Vision

JACKSON, N.J., May 25, 2006    William A. Thornton Jr. died here Thursday of complications following a stroke.  He was 82.

Born June 16, 1923, in Orchard Park, New York, Mr. Thornton graduated from the University of Buffalo, Magna cum laude, BS Physics 1948, and from Yale University, MS Physics 1949, PhD Physics 1951.

Dr. Thornton discovered the ‘prime colors’ of human vision, receiving Westinghouse Corporation’s highest honor, the ‘Order of Merit’  in 1978, “for the development of the prime-color principle....the most important advance in fluorescent lighting in 20 years…and for his many contributions to the understanding of color phenomena.”

In 1979, Dr. Thornton received the U.S. National ‘Inventor of the Year’ award from the Association for the Advancement of Invention and Innovation in recognition of his several basic patents in prime-color electro-luminescence and his pioneer research in human color vision. The holder of 39 U.S. patents, Dr. Thornton’s research and publications spanned the fields of tri-phosphor fluorescence, human color visual sensitivities, colorimetry, color-matching, and color constancy.

In retirement, he founded Prime-Color, Inc., developing and manufacturing state-of-the-art spectro-radiometers and illumination meters based on his continuing research. An ambassador of color research world-wide, Dr. Thornton built and delivered the first spectro-radiometer to the Peoples Republic of China in 1993 and contributed to continuing color research at the University of Nebraska.

Dr. Thornton enlisted in the U.S. Air Force in 1943, studied meteorology and weather forecasting, and served in the European Theater from 1945-1946, Captain, Ninth Air Force.  

A life-long lover of music, Dr. Thornton played clarinet, string bass, tenor and alto saxophone and sang with many barbershop quartets and choral groups, finally with the Jackson Civic Chorus and the Metedeconk Lakes Chorus of Jackson, N.J. He was an active member and President of the Westfield, NJ Old Guard and died a beloved member of the Orchards, Assisted Living community, Jackson, N.J.

Predeceased by his wife, the former Jeanne Marie Schwarzmeier, (1923-1985), Mr. Thornton is survived by his dear friend, Marcia Schoolmaster, sister, Joanne Tolson, his four children, Debora L. Thornton of Ridgefield, CT, Melissa L. Thornton of Trumbull, CT, William A. Thornton III of Sherborn, MA, and Jeffrey F. Thornton of Millington, NJ as well as 5 grandchildren, Erik Thornton Betti, Sarah L. Thornton, Emily, Victoria and Caroline Thornton.

A memorial service in celebration of his life was held at the George Hassler Funeral Home, Jackson, N.J. on Tuesday, May 30 at 2:30p.

Dr. Thornton’s research works are accessible at www.prime-color.com.

In lieu of flowers, please send contributions in his name to any of the following:

1.      Music Lives  at  www.musiclives.org

2.      The National Wildlife Foundation at ww.nwf.org

3.      The Nature Conservancy at  www.nature.org

Dr. WILLIAM A. THORNTON JR., 82, of Jackson, NJ, the 1979 U.S. national "Inventor of the Year," who discovered the "Prime Colors" of human vision, died May 25, 2006 of complications following a stroke.

Born June 16, 1923, in Orchard Park, N.Y., Bill served in Europe during World War II as a Captain of the US Army Air Corps., engaged in weather analysis and forecasting. He then obtained a formal education that included three degrees in Physics: a BS from the University of Buffalo in 1948, and an MS (1949) and PhD (1951) from Yale. He resided in Cranford NJ from 1957 to 2004 and in Jackson NJ from 2004 to 2006. Most of his career was spent at Westinghouse Lamp Divisions (Bloomfield, NJ), but in 1983 he founded Prime Color Inc., and later Prime-Color Lighting, Inc. and Prime-Color Optics, Inc.

Bill is most widely known for his discovery---at Westinghouse---that three wavelengths (which he called "prime-color wavelengths") are particularly important for human vision. The prime-color wavelengths---at about 450, 530, and 610 nm---are the wavelengths for which the following efficiency property holds if they are used for additive primaries (e.g., in a television): No more than one watt of a prime-color primary is needed to match one watt of any other wavelength. Also, the prime-color wavelengths are those at which unit-power monochromatic lights induce the largest tristimulus gamut (volume of the parallelepiped spanned by the tristimulus vectors of these lights). Finally, the zero-crossings of metameric-black reflectances tend to cluster about the prime-color wavelengths. Bill used all these properties to design fluorescent lamps that have high watt-efficiency, good color-rendering capability, and a minimum of metamerism.

By introducing a new class of products (three-band lamps with power concentrations at the prime-color wavelengths), Bill caused a huge company (and actually a whole industry) to change its product focus. His lamp designs made ground-breaking use of rare-earth phosphors, and found a place in several large-scale re-lamping plans. For these efforts, Westinghouse awarded Bill its highest honor, the Order of Merit, in 1978. His basic patents on prime-color lamps also earned him the 1979 Inventor of the Year Award from the Association for Advancement of Invention and Innovation. (For that award, his patents were chosen above 60,000 issuing US patents that year.)

Besides lamp design, Bill applied his prime-color insights to patent protective glasses that transmit light only near the prime-color wavelengths. He also brought the prime-color ideas to bear on fundamental vision theory. In retirement, he founded Prime-Color, Inc., developing and manufacturing state-of-the-art spectro-radiometers and illumination meters based on his continuing research. An ambassador of color research world-wide, Bill built and delivered the first spectro-radiometer to the Peoples Republic of China in 1993 and contributed to continuing color research at the University of Nebraska. Numerous refereed articles document his achievements in these regards. (All told, Bill had at least 44 patents and about 100 published papers.)

One of his later achievements deserves some note. In a three-part paper he published in Color Research and Application (1992), Bill voiced many criticisms of the CIE colorimetry system. One of these criticisms sprang from his experimental observation that the usual linear-algebra transformation between primary sets (as given by Grassmann’s laws) does not predict color matches made by humans. That challenge was the source of a continuing industrial inquiry, culminating in the formation of CIE Technical Committee TC1-56 (Improved Colour Matching Functions) to study the problem. All of color technology depends on resolving Bill’s challenge.

Despite not being an academic, Bill was a true champion of education in the field of lighting and color. Many fundamental articles in JOSA, followed by many in Color Research and Application, were part of his sustained effort to raise the consciousness of the color-science community. Another part of this effort was a column he wrote for Lighting Design and Application. A less visible part was his personal enthusiasm and clarity in engaging in dialogue with others in his field. He did so as well as or better than any university professor we have known in the field. And of course, Bill served the educational objectives of the ISCC well as a Board-of-Directors member and as the Chair of Project Committee 49.

Those of us who attended meetings with Bill will remember his genial invitations to intense dialogue; e.g., "Let’s meet at that clambake and discuss the issue," and "Let’s get a group together and go chew the rag". He never turned down a discussion, and never gave up when someone had not yet seen his point of view. In at least one case, he responded to a disagreeing point of view by inviting the correspondent (MHB) to deliver a formal rebuttal to the Illuminating Engineering Society. This kind of generosity is rare anywhere.

A life-long lover of music, Bill played clarinet, string bass, tenor and alto saxophone and sang with many barbershop quartets and choral groups, finally with the Jackson Civic Chorus and the Metedeconk Lakes Chorus of Jackson, N.J.

Predeceased by his wife, the former Jeanne Marie Schwarzmeier, (1923-1985), Bill is survived by his friend Marcia Schoolmaster; by his sister Joanne Tolson; by his four children, Debora L. Thornton (Ridgefield, CT), Melissa L. Thornton (Trumbull, CT), William A. Thornton III (Sherborn, MA), and Jeffrey F. Thornton (Millington, NJ); and by five grandchildren.

Michael H. Brill and Hugh S. Fairman
InterSociety Color Council Incorporated (ISCC)

The Early Days

In Yale Graduate School, and Brookhaven National Laboratory, physics was always an intriguing field. It became more so, when gamma rays being absorbed in large clear crystals generated winks of blue-violet light, of brightness proportional to the energy of the gamma ray, and effort was needed to work out the performance of that sort of  “scintillation spectrometer.”  Then, at the General Electric Research Laboratory, speedy electrons produced the winks of red, green and blue light to form the colored image of a TV picture-tube, and speedy (but much heavier, and troublesome) ions, in the imperfect vacuum of the TV tube, too-quickly damaged the red- green- and blue-emissions, and the picture faded and turned color. Then, at Westinghouse, different sorts of clear crystals – in powder form – winked in many colors, simply if they found themselves in an electric field; it was an early form of colored-image-forming layer, without the dangerous gamma rays, or the troublesome vacuum to contend with. That led to still different clear crystals glowing blue-violet, green, and orange-red when bathed in ultraviolet light, which ultimately comprised the white layer in the modern Prime-Color fluorescent lamp.

This modern lamplight caters efficiently to the needs of the normal human visual system. It was found that those three particular colored lights – blue-violet, green, and orange-red – are the ones to which the normal human visual system responds most efficiently. Hence the resulting white fluorescence lamplight, formed by mixing proper proportions of the three colored lights (that is, by using a mixture of the three clear-crystal-powders, on the inside of the fluorescent tube), yields the brightest of all possible illuminations. Strangely, also, the coloration of important, identifiable, illuminated objects – like complexions, and foods such as fruit, vegetables, bread, meat, etc. – is particularly pleasant.