I High resolution visible spectrum

  • Thread starter Teck
  • Start date

russ_watters

Mentor
18,524
4,753
To reiterate the accuracy problem, there are several issues:

1. Different people perceive and/or sense them differently.
2. Different monitors display them differently
3. Different color spaces are mapped differently.

That last one I'm not sure was made clear. The image I gave was one of many options:

1920px-CIE1931xy_gamut_comparison.svg.png


Each will give different rgb values for the same wavelength and most even cut off sooner, eliminating the smooshing problem at the ends by stopping sooner.
 

russ_watters

Mentor
18,524
4,753
Not to belabor the accuracy problem, but...

I was wracking my brain to figure out why the color "space" was shown as a plane instead of, you know, a space. I figured it out: the color space is shown at full/flat intensity, so it doesn't represent our perception at varying brightness. This is a problem, because our perception changes completely with light intensity....and intensity sensitivity is different for different colors....and, of course, will vary between people. Dropping this spectrum (which includes that attenuation) into Photoshop:

spectra01.jpg


...gives me a green value of 18 instead of 53 because the green sensitivity is attenuating. Obviously the impact of the attenuation is most pronounced at the ends of the spectrum. So again, even though I can easily get per nanometer values from this picture, I don't think it's a very useful exercise (even though I'm not sure why you are doing it...) because:

1. The values will vary from one person to another.
2. The values will vary from one monitor to another.
3. The values will vary from one color space to another.
4. The values will vary with light intensity.

By the way; the above graph may be easier to pull the data from if you think it's valid data. You could pull every 10 nm and use a spreadsheet to linearly interpolate down to 1. You should be able to do that in 10 minutes instead of an hour for trying to read every 1 directly from the previous graph.
 

pinball1970

Gold Member
394
342
I'm trying to find a high resolution image that shows the visible electromagnetic spectrum with a fine graded scale. It should be detailed enough to pinpoint which exact colour corresponds to a particulate wavelength (integer in nanometer) of light. I find a lot of images through searches but noone that is detailed.

For example, if we say 503 nm. I want to be able to find which exact colour corresponds to that wavelength.

The importance here is the accuracy of the colour (and I know different monitors can display colours differently, but let's not get into that :D )

Please link such an image.
All the guys have gone through the physics, electronics.
Colour is very subjective because every eye, retina, distribution of photo receptor cells, type of cells, proteins are different. Even one eye to the other in the same head!
Also the eye does not 'see' colour the brain does, how different is every brain?
Ten colourists all stood round the same calibrated colour screen will see the same red differently and will never be able to articulate anything about it that has any sort of meaning.
One could agree on spectral values from 400-700nm, the numbers but what would that mean?
It would be like reading a recipe for pea soup then guessing what it tastes like.
 

Want to reply to this thread?

"High resolution visible spectrum" You must log in or register to reply here.

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top