Expert: Florence M Rollwagen - 8/11/2008

Question
This is difficult for me to understand so I'm going to explain as best as i can.
When we are little we are all taught which color is which. For example..a teacher shows us an orange piece of paper and we are told that  piece of paper is orange. So say 2 g people were shown that same piece of paper...we would both agree that is it orange because we were taught that when we see that color its orange. However...do we both see orange the same way? If it were possible...and I looked through the other persons eyes would the color they see as orange look maybe..blue for example to me?

Answer
Hi Sarah:  Thanks for your question.  The colors of the visible spectrum (think: rainbow) are determined by the wavelength of light.  For a good explanation of this look at this site from NASA:
http://eosweb.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html

We all agree that wavelengths of a given size represents a given color.  It's not that we see different colors with our eyes and are told to call them by various names.  A given color does not "emit" light, rather it absorbs all other wavelengths and reflects the one we see.  For example, a plant is green because it absorbs red, blue, yellow, etc and NOT green.  Green is reflected.  So your orange piece of paper is orange because it absorbs all the other colors and reflects orange.

The parts of our eye that see color are activated by certain wavelengths.  So the wavelength of orange activates the orange cones (eye parts) and our brain sees that wavelength.  The name we use is not relevant since we all use different languages.
We call it "orange" instead of Eoiuc because that's the word we use.  

Some people who are color blind cannot distinguish between red and blue.  This is because the cones of their eyes cannot see those wavelengths, not because of interpretations, but because of the physics of light.

I hope this answer has helped you.  Please write back if you have more questions.

FM Rollwagen, PhD