Designing a Portable Automatic Recording Spectro-Photometer

The history of color dates back to pre-historic times. The cave dwellers of that period, through their sketches on the stone tools of their caves, have given us actual proof that they studied Mother Nature in color as well as in action, and tried to imitate her none too often unsuccessfully. Until recently a means of representing colors was unavailable to the dye industries, excepting of course the trial and error method with its inaccuracy coupled with that of the eye, that remarkable but unreliable agent. On becoming fatigued, the reliability of the eye rapidly diminishes. We have all seen how the camera has replaced the eye as a permanent recorder of shades and shadows, but even this device has not the capacity to reproduce the color of the desired object. If it did possess this property the reproduction would fade with age, rendering the record inaccurate. In 1903 Ives stated that the only true way to record a color in permanent form would be by graphical representation, and the graph to be determined with no less than twenty-five points taken at equal intervals across the visible region of the spectrum. To design a means to automatically trace a continuous curve or graph representing the color of the sample would be to realize the ideal condition.The object of this thesis is to present in part the analysis involved in a possible solution to the problems encountered in the design of an automatic color recorder - more scientifically termed an automatic recording spectro-photometer.