Science Fair Projects

Quantifying the Effect of Tungsten Illumination on Color Rendering of Low-Pressure Sodium

Abstract

The objective: Low-pressure sodium vapor (LPS) is efficient and astronomer-friendly lighting, but its narrow band of emissions results in poor color rendering of illuminated objects. This experiment determines whether a model can be developed to predict the amount of broader-spectrum incandescent illumination required to supplement LPS in order to render near normal color perception.

Methods/Materials

Using a digital camera, I took over 1600 images of six Newtonian color targets illuminated by 4300 lux from an 18-watt LPS lamp and variable lux from a 100-watt tungsten lamp, ranging from 0 to 3080 lux regulated by a dimmer and measured photometrically. I developed a C++ computer program to convert RGB pixel data of each CCD image into CIE L*a*b values and to calculate delta E color differences against a 100% tungsten color reference. I established a "Color Rendering Value (CRV)" from 0-100 for each sample, based on a weighted average of the delta Es of the Newtonian spectrum. CRVs of samples were averaged and graphed to determine a best-fit mathematical correlation to CRV as a function of tungsten percentage.

Results

The CRV for illumination with 2.5% tungsten was 2.3, 3.4 with 15.0%, 13.7 with 26.0%, 30.1 with 35.9%, and 41.2 with 42.7% tungsten illumination. A model correlating tungsten percentage, "W", to color perception as indexed by CRV was derived: CRV = 38 arctan(.07 W - 3.2) + 49.5, with acceptable color rendition at CRV > 13.

Conclusions/Discussion

The results of this experiment indicate that LPS lighting augmented by approximately 26% tungsten illumination may render near normal color perception, with higher standards achievable with higher amounts of tungsten illumination. Applications of LPS combined with broader-spectrum illumination may present an alternative for outdoor lighting that is both color-acceptable as well as cost-efficient and environmentally responsible.

This project examines the effect of tungsten illumination on color rendering of low-pressure sodium vapor light using computer analysis of CCD pixel data and derives a model correlating color perception to percentage of tungsten.

Science Fair Project done By Jessica J. Rucker

 

Related Projects : The Focalization of Sound, Specific Heat in Materials, Quantifying the Effect of Tungsten,Color vs. Heat Absorption, Wavelength Controlled Holographic Polarization, Swing, Pendulum, Swing, Creating Sound with Heat, How Do Various Nonwoven Medical Gowns Compare as Barriers Against UV Radiation, Chemiluminescence, Effect of Ammonia Gas on Copper Nanowire Sensors, Brass Instruments and Artificial Lips, How Accurate Is Parallax, Doppler Effect and the Fiber Gyroscope, Radioactive Attenuation and the Inverse Square Law, Effect of Color on the Characteristics of a Heat Barrier Material

 

<<Back To Topics Page........................................................................................>> Next Topic

 

 

Copyright © sciencefairprojects.co.in 2013 through 2015