continued... Light, Color, Filter, Jos. Schneider Optische Werke
. Electromagnetic radiation
The total range of this radiation can be divided into radio waves, radar waves, heat rays, light rays, ultraviolet rays, X-rays and Gamma rays. All these rays obey the same laws despite the fact that they appear very different to human sensing systems and that technology requires the most various devices to master them. Electromagnetic waves can also spread in a vacuum. They are then at the same speed for all frequencies.
Electromagnetic radiation of varying intensity and wave-length capable of causing an impression of brightness and color in the human eye. Most light sources radiate mixed light, consisting of different light colors. The wave-length is used in optics to characterize these colors.
Light energy increases as wave-length decreases. Blue light has more energy than red light. The nature of light has not yet been explained exactly. The best explanation has been offered by the quantum theory: "Light consists of particles which often behave like a wave." Light as defined by photography is all radiation between 320 and 1050 nm. Outside these wave-lengths, special equipment such as quartz lenses and photon amplifiers necessary in order to create pictures.
Color is the psychological response of the eye to electromagnetic radiation between 380 and 780 nm
. Color sensing is operated via three different sensing systems for blue, green and red. Color film, color selection techniques and color television are based on the way the eye sees color for their theoretical construction.
The color chart is a system based on standard light types and on the average human color feeling, allowing accurate placing of a color on a graph by means of numerical values. For better orientation, the light colors have been added in Fig. 1 as in the curve diagrams. Likewise, the names of many B+W filters can be found.
Light color Wave-length in
Ultraviolet A 320 to 370 Violet 370 to 410
Indigo-blue 410 to 430
Blue 430 to 480
Bluish-green 480 to 500
Green 500 to 540
Yellow-green 540 to 560
Yellow 560 to 580
Orange 580 to 610
Red 610 to 650
Dark red 650 to 780
Infrared A 780 to 1400
"Popp also knew that patients with xeroderma pigmentosum eventually die of skin cancer because their photorepair system can't repair solar damage. He was also struck by the fact that photorepair works most efficiently at 380 nm -- the same frequency that the cancer-causing compounds react to and scramble.
This was where Popp made his logical leap. If the carcinogens only react to this frequency, it must somehow be linked to photorepair. If so, this would mean that there must be some kind of light in the body responsible for photorepair. A compound must cause cancer because it permanently blocks this light and scrambles it, so photorepair can't work anymore. It seemed logical, but was it true?"