# B Color and temperature

#### revv

In my quest to understanding radiation of the electromagnetic spectrum and the things around me I would like to confirm if I understand this correctly...

- The color of objects around us doesn't always mean they are hotter than another just because of the color it has, for example: A blue balloon isn't hotter than a red balloon (even though blue light IS hotter than red light?) they are equal in temperature and the only reason for the color is from dyes in the balloons is this correct?

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#### pinball1970

Gold Member
In my quest to understanding radiation of the electromagnetic spectrum and the things around me I would like to confirm if I understand this correctly...

- The color of objects around us doesn't always mean they are hotter than another just because of the color it has, for example: A blue balloon isn't hotter than a red balloon (even though blue light IS hotter than red light?) they are equal in temperature and the only reason for the color is from dyes in the balloons is this correct?
Reflected light is different from the colour from a black body, I made the same mistake when I first looked into it. Sophicenture explains this very well. Colour from a black body is related to temperature, reflected light is related to the chromophores

#### revv

Reflected light is different from the colour from a black body, I made the same mistake when I first looked into it. Sophicenture explains this very well. Colour from a black body is related to temperature, reflected light is related to the chromophores
I see, I have NEVER heard of Chromophores before!

But the light reflected from objects is it still electromagnetic radiation? I think I understand that the color of an object is the one that is reflected and the other ones absorbed but is the same thing happening with Chromophores?

#### revv

Well from this description of Chromophores on wikipedia I think I understand a little more but not entirely sure, it's a new word for me.

"Leaves change color in the Fall because their chromophores (chlorophyll molecules) break down and stop absorbing red and yellow light"

Is Chromophores just a change in how things absorb the light over time? Like They go from green to red and yellow because of chromophores?

Is chromophores only related to biological matter?

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#### pinball1970

Gold Member
Well from this description of Chromophores on wikipedia I think I understand a little more but not entirely sure, it's a new word for me.

"Leaves change color in the Fall because their chromophores (chlorophyll molecules) break down and stop absorbing red and yellow light"

Is Chromophores just a change in how things absorb the light over time? Like They go from green to red and yellow because of chromophores?

Is chromophores only related to biological matter?
Yes it's all still magnetic radiation interacting with cells in our retina that tell us what colour something is. It does not necessarily have to be biological, dyes inks ores oxides and certain salts all can be coloured as well as trees flowers people and birds.

#### Demystifier

2018 Award
A LED bulb is quite cold, despite of producing a "white" light.

#### pinball1970

Gold Member
A LED bulb is quite cold, despite of producing a "white" light.
I don’t know enough of the physics or electronics.

All I know is an LED unlike incandescent does not convert much of the energy/ electricity to heat which is one of the reasons they are far more energy efficient.

Or do you mean warm and cool as in CCT?

It’s the wrong way round for lamps, cool such as 6500 has higher CCT than a “warmer” light which tend to be in the 2-3K range.

#### revv

"It does not necessarily have to be biological, dyes inks ores oxides and certain salts all can be coloured as well as trees flowers people and birds. "

And all of those mentioned things is the result of chromophores?

If the color of an object isn't because of heat is it chromophores?

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#### hutchphd

"It does not necessarily have to be biological, dyes inks ores oxides and certain salts all can be coloured as well as trees flowers people and birds. "

And all of those mentioned things is the result of chromophores?

If the color of an object isn't because of heat is it chromophores?
Often but not always. For instance the colors of a soap bubble (or an LCD screen for that matter) are due to interference and geometry. This is a very large subject, worthy of a life of study.....
Can anyone suggest a really good elementary reference?

"Color and temperature"

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