K. L. and B. J. Kosanke
ABSTRACT: A simple, low-cost visible light spectrometer, consisting primarily of a video camcorder and an inexpensive diffraction grating, was assembled and found to be of use in work to improve colored pyrotechnic flames. This instrument is all that is needed to collect and store useful, qualitative flame color information. With this simple instrument, the nature of color agents and the sources of interfering chemical species can be determined.
If semi-quantitative data is needed, a video frame grabber and personal computer can be employed. These allow more accurate identification of wavelengths of spectral features (lines and bands). It also makes possible the determination of relative intensities of spectral features. If quantitative intensity data is needed, a suitable calibration source is necessary and calibration corrections must be applied to the intensity data.
In a brief study using the video spectrometer, it has become clear that much of the difficulty in achieving high quality green and blue colored flames is often the result of impurities present in the raw chemicals. Specifically, the presence of sodium and calcium can act significantly to shift green flame colors toward yellow and blue flame colors toward white.
Keywords: spectroscopy, flame color, video
Ref: Selected Pyrotechnic Publication of K.L. and B.J Kosanke, Part 5, (1998-2000), pp 1-12
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