Prism Spectrum for Color Calibration
Re: Prism Spectrum for Color Calibration
Tom Axford wrote:
petrochemist wrote:
Tom Axford wrote:
petrochemist wrote:
Tom Axford wrote:
SmoothOperator wrote:
I'm wondering, why use these expensive color charts for color calibration, when you could get the real thing from a prism.
There are infinitely many more colours than those in the spectrum. Most real colours are mixtures (e.g. browns) and do not occur in the spectrum which consists only of "pure" colours.
The are other colors yes but not many more. The spectrum consists of a near infinite variety of subtly changing colors.
You have already contradicted yourself in just two sentences!
Actually the main contradiction is in just two words 'near infinite'
The wavelength of a photon is quantized so the number of colors between two wavelengths is not actually infinite, but the steps are very small. Hence the meaning less phrase 'near infinite' to imply a huge number. Visual light is roughly 400-700nm. I've come across wavelengths specified to 4 or more decimal places, (such as the sodium D lines at 588.9950 & 589.5924nm ) so at the resolution of the data I've seen that's ~3million pure colors - I believe the quantum steps in wavelength are actually considerably smaller variations, and I've never come across or heard of an instrument capable of resolving them.
I have never heard of a 'quantum of wavelength' before, but if such exists, what value does it take? Perhaps the Planck length, which is about 10^(-35) metres? On that assumption, there are well over 10^20 separate wavelengths within the visible spectrum!
I think this is all very much in the realm of speculation. I've never heard of any experimental confirmation of this. Are you aware of any?
Sounds about right hence my 'near infinite'. No I've never come across experimental confirmation. If the theory is wrong & wavelength is a true continuum then there are an infinite number of wavelengths & an infinite number of pure colors.
Of course neither commercial digital cameras or the human eye can resolve anywhere near this number of colors. Sensors in some astronomical gear can resolve impressive numbers (as produced in their stellar spectra) but they're not exactly pocketable systems
Pentax K100D
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