Spectral Art: Photographing the Light Spectra of Gases in Electric Discharge Tubes

SPECTRALART: PHOTOGRAPHING THE LIGHTSPECTRA OF GASESIN ELECTRIC DISCHARGE TUBES Ronald A. Brown, Physics Department, State University of New York at Oswego, Oswego, NY 13026, U.S.A. Gary Burgess, R. D. 3, Speach Drive, Central Square,New York, NY 13136, U.S.A. Received 3Apn'lI989. Acctptedforpublication by Roger Malina. Since the mid-1970s I (R.Brown) have worked with a number of students at State University of New York at Oswego in the general area of developingmodes of artistic expression through the application of physical principlesto art and photography. Thiswork, which I carry out with coresearcherssuch as co-authorG a r y Burgess,has alwaysbeen self-generated , and we simply choose areas that appeal to our artistic sense. Previously published work has included polarized light art [11,and the present note discussesthe photographing of light spectrafrom gasesexcited by high voltage in electricdischarge tubes, research that was carried out during the years 1976-1977. The spectra were photographed using diffraction filters,which are multi-axisdiffraction gratings [2] created using laser-holographic techniques [3]. These filters produce colorful spectral orders in dramatic star-likepatterns . Figure 1shows the experimental setup for photographing the spectra. Typicalgases used include: helium, neon, water vapor, krypton, mercury vapor and argon. A 5,000-volt power supplywith a current-limitingregister was used in a light-shielded room [4]. Spectrum tubes were used singly and in pairs to vary the light intensity, exposure time and f-stopopening. If the exposure time is sufficientlyshort, evidence of the experimental apparatus can be completelyeliminated from the final photograph. Our best results came from photographing the spectrum of helium using a 50-mm f/1.7 lens,with a Ssec exposure time and an f 4 lens opening. The film was Kodak type ER 5257with a daylight ASA of 160,which was processed using the Kodak E4 chemistry.Color Plate B No. 3 shows the characteristic star-shaped spectrum in what we believe to be an aestheticallypleasing result that enhances the beauty of the spectral lines. The basic experimental technique is quite simpleand, with some patience, striking photographs can be obtained. ical principles of diffraction gratings to create an art form, spectralart, from the optical spectrum of a gas excited under high voltage in an electric dischargetube. This research rep resents one aspect of our ongoing search for new methods of artistic expression by the application of physical principles to selected areas of art and photography. Referencesand Notes In summary,we have used the phys1 . R A. Brown, "Figurative'PolarizedLight Painting ':Staticand KineticTypes",Leonurdo10, No. 3,213-214 (1977). 4 . F. W. Sears, M. W. Zemansky and H. D. Young, UniumilyPhysics (Reading,MA: Addison-Wesley, 1987) pp. 934-937. 3. Searset a l . [2] pp. 943-945. 4. The filterused is known by its wade name Spectralstar (Filterno. DS-8);ocherversions, suchas the Cokin 041 Diffractorunivers (Cokin Filters, 101 WilliamsDrive, Ramsey, NJ 07746, U.S.A.),are alsoavailablecommercially.Inexpensive ,unmountedversions of diffractionfiltersare availableunder the namesRainbowDisk (Jertyco,Inc., 601 Linden Place, Evanston, 1L 60202,U.S.k)and Color Burst Filter (Edmund ScientificCo., 101 E. Gloucester Pike,Barrington , NJ 08007-1380, U.S.A.). Fig. 1. RonaldA. BrownandGaryBurgess,experimentalsetup forphotographingthe lightspectrumofa gas i n anelectric discharge tube using amulti-axis diffractionfiter. HighVoltage \ Tube Camera / ' + \CurrentCimitingResistor 01990ISAST PergamonPresspic. PrintedinGreatBritain. 0024094)(/90$3.00+0.00 LEONARD0,Vol.23, No. l.,pp. 139-141.1990 139 ...