Newton, Goethe and the Process of Perception: an approach to Design

Figure 3 Figure 4

Figure 3 now presents a series of three white slits on a black background, the slits getting narrower in sequence. The effect is that the two fringes of red/orange/yellow, violet/indigo/blue progressively come closer but their widths appear to remain constant. In the lowest slit the blue and yellow seem to have overlapped and disappeared, with green appearing in their place! So here is an interesting phenomenon. Green is being perceived subjectively although there was no trace of it for the wider slits. If green is defined objectively as a narrow range of wavelengths of light, then the fringes of the wider slits demonstrate that it is not there to be seen in its own right. But where, for the narrow slit, the yellow and blue appear to combine, green is seen subjectively, in spite of the objective fact that its spectoscopic wavelength range does not extend into the spectroscopic ranges of yellow and blue. Figure 4 then produces an even more startling phenomenon. Here black slits are presented on a white background and as the fringes of blue/indigo/violet and yellow/orange/red come together, when the red and violet strips seem to overlap the overlap is magenta - and magenta is not even a colour in Newton's spectrum!