- #1
fargoth
- 320
- 6
im reading some of feynman's lecture notes, and i stumbled upon a statement which i do not understand...
he says that we can use ANY three different colors to produce any other color.
lets say we want to see the color X, and we use yellow blue and red (Y,B,R)
then X = yY + bB + rR.
where y,b and are are the color coefficients.
inorder to produce some colors (in my example let's say we want to get green) we would need to use a negative color coefficient.
i.e. the r should be negative while y and b have some positive value to produce green.
mathematically i can see it is so, but i couldn't understand how you practically make it... i'll give you the original quote:
now, what does he mean when he says "to add them to the other side"?
does he mean that if i use three flashlights with red, yellow and blue colors, we have to use the red flashlight from one side of a sheet and the other two from the other side?
doesn't sound right to me...
can someone explain what he means?
how can i produce green in the lab using red, yellow and blue flashlights?
he says that we can use ANY three different colors to produce any other color.
lets say we want to see the color X, and we use yellow blue and red (Y,B,R)
then X = yY + bB + rR.
where y,b and are are the color coefficients.
inorder to produce some colors (in my example let's say we want to get green) we would need to use a negative color coefficient.
i.e. the r should be negative while y and b have some positive value to produce green.
mathematically i can see it is so, but i couldn't understand how you practically make it... i'll give you the original quote:
By mixing these three colors in various proportions, we get quite an array of different clors, ranging over quite a spectrum. But as a matter of fact, after a lot of trial and error, we find that nothig ever looks like green.
The question is, can we make green? The answer is yes. How? by projecting some red onto the green then we can make a match with a certain mixture of yellow and blue! so we have matched them, except we had to cheat by putting the red on the other side.
But since we have some mathematical sophistication, we can appreciate that what we really showed was not that X could always be made of, say, red, blue and yellow, but by putting the red on the other side we found that red plus X could be made out of blue and yellow.
So if we allow that the coefficients in the equation can be both positive and negative, and if we interpret negative amounts to mean that we have to add those to the other side, then any color could be matched by any three, and there is no such thing as "the" fundamental primaries.
now, what does he mean when he says "to add them to the other side"?
does he mean that if i use three flashlights with red, yellow and blue colors, we have to use the red flashlight from one side of a sheet and the other two from the other side?
doesn't sound right to me...
can someone explain what he means?
how can i produce green in the lab using red, yellow and blue flashlights?