Spectrophotometry: Light Transmittance & the Instrument that Transformed Chemical Analysis (ONLINE EXHIBIT)

This online exhibition explores Dr. Arnold O. Beckman's impact on our understanding of the field of spectroscopy (how light interacts with matter) and the technique of spectrophotometry (how light transmittance/absorption are measured in a chemical substance), and his subsequent influence within both the manufacturing space and the scientific community following the introduction of the Beckman DU Spectrophotometer during World War II.

Building upon his earlier awareness that Beckman Model G pH meters (and similar product designs by other companies) could be used as electrical signal amplifiers for other analytical instruments, Dr. Beckman focused his company's research and development efforts on creating a spectrophotometer of his own design. His fourth model, the Beckman DU Spectrophotometer, vastly improved upon previous instruments offered industry-wide, driving sales for the company and speeding the pace of research.

The objects, images, and documents in Spectrophotometry: Light Transmittance & the Instrument that Transformed Chemical Analysis capture this groundbreaking work in chronological fashion.

The online exhibit is accessible below for viewing here, or on its host platform. Its mp4 file format was rendered in high definition (1080p). Sound runs throughout (“Prism” instrumental music track by Aim for the Moon) but can be muted, if preferred. The viewer can also pause the presentation to allow for additional time reading photo interpretations. A dotted progress bar near the bottom indicates the viewer journey through the slides. Run time is 5:49 minutes.

Viewing tip: Enlarge the video to the size of the browser, or switch to the host platform and select HD.

Except where noted (see References), images depicted in the Spectrophotometry online exhibit were sourced from the Beckman Foundation Collection and are property of the Arnold and Mabel Beckman Foundation. As such, they may not be copied, reproduced, used, stored, or sold without written permission.

Viewers can also access PDFs of the online exhibit slides in parts using the following document links:

When curating online exhibits, it’s always with the intention of providing greater access to the Foundation’s extensive archival collection of images, objects, and documents – items which offer a window into history told through the lens of scientific accomplishment. This exhibition echoes that intention and introduces online viewers to our first presentation exclusively focused on a scientific instrument, the Beckman DU Spectrophotometer. Our goal in spotlighting the DU first was to emphasize the important role it played in speeding the pace of research; to accentuate how transformative it became to chemical analysis – and hence, our title.

The approach we used in the exhibition was to break down the science concept, the measurement technique accomplished by the instrument, to explain the gap in the marketplace, describe the unique design that Dr. Beckman and his team created with the DU to address that gap, and then highlight some of the scientific breakthroughs that resulted from the instrument’s robust capabilities. A selection of custom illustrations, product advertisements, photos, schematics, press documents, graphics, and quotes were included to chronologically re-capture the groundbreaking work of Dr. Beckman and his team. Of particular note are two photographs that give the exhibit unique perspective, showing the making of the DU spectrophotometer from the inside and the outside: the first is an exterior look at the 1940s Pasadena location of National Technical Laboratories, part of the Beckman Foundation Collection, and the second is a William Connell photograph of quartz crystal shown before it was cut for use in the DU, part of the Science History Institute Collection.

Our prior online exhibits covered Dr. Beckman’s role in the fight against smog in Los Angeles, delved into the personal photo scrapbook of Mabel Beckman, and looked at the Beckman innovation that helped make U.S. space exploration possible. This exhibit is a bit of a pivot in that it considers Dr. Beckman’s impact on our understanding of an entire field (spectroscopy) and a technique (spectrophotometry), and the influence resulting from the success of the Beckman DU Spectrophotometer. It’s significant because it shows Dr. Beckman evaluating a potential entry point in the market with spectrophotometry, and it represents a moment where he took a leap and essentially had to control every part of the design and manufacturing processes to see success. He managed to do all of that and struck gold, not just for himself though – as Nobel Laureate Bruce Merrifield pointed out, he designed, “probably the most important instrument ever developed towards the advancement of bioscience.”

KR

Introduce kids to the wonder of science with three different coloring pages and learn about instruments pioneered by Dr. Beckman and Beckman Instruments. Each design is available as a printable PDF and includes information about our Let's Learn Science online lesson plans.

The Revolutionary Tools Exhibit is located at the Arnold and Mabel Beckman Center for the National Academies of Sciences and Engineering in Irvine, Ca. It includes a section dedicated to the DU/IR Spectrophotometer. Below, listen to an audio tour of the information from that section of the exhibit hall.

• Explore spectrophotometry-themed lesson plans for middle school students designed with grade-specific activities and NGSS standards in mind (click to select):

• Read this article by Arnold O. Beckman and H. Howard Cary, reprinted from the Journal of the Optical Society of America Vol. 31, No. 11, November 1941, presented at the Ninth Summer Conference on Spectroscopy and Its Applications, held at the Massachusetts Institute of Technology during July of the same year.

• Watch this video from Beckman Foundation's YouTube channel titled, "DU Spectrophotometer," uploaded in 2017, to learn more about this pivotal invention which forever changed chemical measurements in labs and manufacturing:

• Read “New Light on the Molecular World: The Spectrophotometer Revolution” by R.B. Woodward

Keywords: Chemical research, spectrometry, spectroscopy, spectrophotometry, spectrophotometer, absorption spectrum, light wavelengths, quartz prism, ultraviolet light, chemical analysis, photoelectric, phototubes, amplifier, Beckman, pH meter

Some text for this exhibit and webpage sourced from:

Ray, K. A. (2025). A Laudatory View of Arnold O. Beckman’s Impact on the Understanding of Spectrophotometry and Influence on its Practical Application [Unpublished]. C&IS Application, University of Alabama.