Investigations have been done with high-brightness LEDs in order to determine the flight of colors for these high-intensity
light sources. By simply glancing into such a device for time durations of less than 10 seconds a long-lasting
afterimage that slowly changes colors was observed.
A computer assisted measuring system was developed in order to determine the dependency on various parameters like
color, optical power, exposure duration of the stimulating LED. For that a specially designed color wheel diagram has
been designed and used which contains the necessary information on hue, saturation, and brightness.
The time-dependent process and changes of the afterimage colors were determined for 4 different dominant wavelengths,
i.e. 455 nm, 530 nm, 590 nm and 625 nm, in the optical power range between 0.05 mW and 0.5 mW for exposure
durations between 0.5 s and 5 s. The results obtained with 5 test persons will be reported and especially the time course
of the color fractions is given in an 8-bit color space with the respective RGB values. The progression of the afterimage
colors as a function of the applied optical energy will be shown in the CIE chromaticity diagram together with the
respective total afterimage duration.