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Prism Spectrum for Color Calibration

Started Jul 2, 2018 | Questions thread
petrochemist Veteran Member • Posts: 3,619
Re: Prism Spectrum for Color Calibration

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.

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