0
\$\begingroup\$

There are various bulb products in the market, the temperature of the bulb determines the colour of the light emitted by the bulb.

For example

3000K is warm white (yellowish)

6000K is daylight (white)

Is there any correlation between energy used and colour temperature? Does colour temperature determine energy consumption?

Is it possible to get a different colour temperature by putting a filter in front of the bulb? For instance is it possible to put a filter in front of a warm white bulb to get daylight?

\$\endgroup\$
11
  • 1
    \$\begingroup\$ Filters don't add light. They only remove it so they can shape the colour profile to be something else but it will always be dimmer. Potentially a lot dimmer. \$\endgroup\$
    – DKNguyen
    Apr 24, 2020 at 13:59
  • \$\begingroup\$ Do you have a specific type of bulb in mind? LED behaves very differently than incandescent light for example. LED color is completely determined by the semiconductor material used (chemical composition) but incandesent bulb color is determined generally by filament temperature. (Colored) filters behave very differently between LEDs and incandescent lights. \$\endgroup\$
    – StarCat
    Apr 24, 2020 at 14:00
  • 2
    \$\begingroup\$ For an incandescent bulb, the color temperature is the actual temperature of the filament. The filament follows the blackbody radiation laws fairly closely. en.wikipedia.org/wiki/Black-body_radiation . For other bulb types it is a lot more complicated. \$\endgroup\$
    – Mattman944
    Apr 24, 2020 at 14:01
  • 2
    \$\begingroup\$ @StarCat - for white LEDs, color temperature is largely determined by phosphors, not the LED emission spectrum itself. \$\endgroup\$ Apr 24, 2020 at 14:08
  • 1
    \$\begingroup\$ When you mention energy do you really mean efficiency? Be specific, for lights there is luminous efficiency (how bright it looks per watt), photon efficacy (photons per joule), and wall plug efficiency efficiency (watts of light per watts of electrical power). These are often very different so be clear which you mean. \$\endgroup\$ Apr 24, 2020 at 14:38

1 Answer 1

1
\$\begingroup\$

Is there any correlation between energy used and colour? Does colour determine energy consumption?

Minuscule, there are an awful lot of other design considerations that will have drastically larger impacts on consumption in both incandescent and LED.

Is it possible to get a different colour temperature by putting a filter in front of the bulb? For instance is it possible to put a filter in front of a warm white bulb to get daylight?

Yes, but it is always going to remove intensity of the light at its destination. Take a warm light bulb, a filter (neodymium I believe) that filters out some of the reds and yellows and it'll appear more like daylight (bluer), but will be less intense when measured because you're blocking some of the source light.

The world is significantly different with the various materials used in LEDs - if you are interested in what makes the colors what they are, go to a white and then any color data sheet and it will talk about the different materials (AlInGaP, InGaN, etc) that are used to make it appear the color it is.

Note: this being a simple question, the answer has been simplified... there is so much more to the world of light!

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.