WE NEED SPECIFICATIONS
FOR COLORED LIGHT BULBS


WHAT DO WE NEED?

We need the ability to measure standard values for colored light:

We also need a measure of the life of any lightbulb - one that actually works:


WHY DO WE NEED IT?

People do not know what they are getting when they buy a colored light bulb.

There are a lot of uses for colored light bulbs other than illumination at a party:

Many of the colored light bulbs offered for sale do not produce light that is usable for many of these purposes. The page author has found at least 4 different kinds of colored LED light bulbs on the market:


WHAT CAN BE DONE?


WHAT CAN BE USED?

There are several ways this information can be measured:


THE BULBS

Appendix 1: Comparing Colored LED Bulbs

Here are the approximated values of various brands of colored LEDs:

COLORED LIGHT BULB PROPERTIES

BRANDLABEL
COLOR
BRIGHT
chromen
HUE
nm or K
SAT. %
or CRI
PSEUDO SPECTRUM COMMENT

                                                     

Feit Daylight 450 lm 5000 82

                                                     

Reference white LED (note spectral gaps)
Feit Red 115 610 90

                                                     

Useful as primary red
Illumin8 Red 68 620 95

                                                     

Narrow band - useful as primary red
Utilitech Red 63 620 95

                                                     

Useful as primary red
Zilotek Red 104 620 80

                                                     

Wide-band simulation of incandescent
Christmas Valley Red 4 620 97

                                                     

Narrow band - useful as primary red
Great Value Red 79 595 30

                                                     

Filter cap on white LED
Feit Orange 103 590 85

                                                     

 
Illumin8 Orange 45 590 95

                                                     

Narrow band
Utilitech Orange 56 590 95

                                                     

 
Feit Yellow 131 577 80

                                                     

 
Illumin8 Yellow 47 580 95

                                                     

Narrow band amber - dichromat simulation use
Utilitech Yellow 63 575 90

                                                     

 
Christmas Valley Yellow 4 577 95

                                                     

Narrow band - useful as monochrome yellow
Great Value Yellow 435 575 30

                                                     

Filter cap on white LED
Feit Green 182 520 90

                                                     

Useful as primary green
Illumin8 Green 123 500 90

                                                     

Narrow band - useful as primary green
Utilitech Green 156 500 90

                                                     

Useful as primary green
Zilotek Green 113 530 40

                                                     

Wide-band simulation of incandescent
Christmas Valley Green 12 510 90

                                                     

Narrow band - Useful as primary green
Great Value Green 51 500 30

                                                     

Filter cap on white LED
Feit Blue 79 480 70

                                                     

Useful as cyan
Illumin8 Blue 64 470 80

                                                     

Narrow band - useful as primary blue
Utilitech Blue 42 470 85

                                                     

 
Zilotek Blue 17 440 35

                                                   

Wide-band simulation of incandescent
Christmas Valley Blue 5 460 87

                                                     

The case fluoresces dimly yellow
Great Value Blue 28 440 20

                                                     

Filter cap on white LED
Utilitech Purple -560 76 55

                                                     

 
Utilitech Pink -500 113 50

                                                     

 
Great Value Pink -500 113 50

                                                     

 

For white lights:
- The BRIGHT column contains lumens, not chromens.
- The HUE column contains color temperature, not wavelength.
- The SAT column contains the Color Rendering Index (CRI).


Appendix 2: Measuring LED Bulbs

Here us the procedure to measure the various parameters of colored LEDs:

Preparing:

  1. Get the needed equipment:
  2. Set up the equipment:

    Be sure the area can be darkened.

  3. Calibrate your setup with several known bulbs:

    When in doubt, experiment. Adjust the lamp angle and the entered shadow angle.

Collecting the Data:

  1. Get information from the bulb:
  2. Take readings from the bulb:
  3. Do the calculations:

    Put one bulb in each row of the spreadsheet.

    Enter the following in the spreadsheet:

    When dealing with colored light, substitute the proposed chromen unit of measure for the lumen.

    • Footcandle Calculations

      The setup was purposely designed so the number of footcandles is equal to the number of candelas.

      Meter uses Footcandles, Set up for Footcandles
       A BC D EF GHI
      1PRODUCT fccd nom lm or cr shad angsphere difference unshaded partbright portionlm or cr
      2FEIT 40 Red LED 14.514.5 182 1500.741181 7.909390.62941115
      3Formulas for above 14.5= B2 = C2 * 4 * PI() 150= 1 - COS(E2 / 2 * PI() / 180) = 4 * PI() - 2 * PI() * F2= G2 / 4 / PI()= D2 * H2
    • Lux Calculations

      The setup was purposely designed so the number of lux is equal to the number of candelas.

      Meter uses Lux, Set up for Lux
       A BC D EF GHI
      1PRODUCT lxcd nom lm or cr shad angsphere difference unshaded partbright portionlm or cr
      2FEIT 40 Red LED 14.514.5 182 1500.741181 7.909390.62941115
      3Formulas for above 14.5= B2 = C2 * 4 * PI() 150= 1 - COS(E2 / 2 * PI() / 180) = 4 * PI() - 2 * PI() * F2= G2 / 4 / PI()= D2 * H2
    • Lux Meter With Footcandle Setup Calculations

      The setup was designed so lux must be converted to footcandles to get the number of candelas.

      Meter uses Lux, Set up for Footcandles
       A BC D EF GHI
      1PRODUCT lxcd nom lm or cr shad angsphere difference unshaded partbright portionlm or cr
      2FEIT 40 Red LED 15614.5 182 1500.741181 7.909390.62941115
      3Formulas for above 156= B2 * 0.0929 = C2 * 4 * PI() 150= 1 - COS(E2 / 2 * PI() / 180) = 4 * PI() - 2 * PI() * F2= G2 / 4 / PI()= D2 * H2

    When in doubt, again experiment. Adjust the lamp angle and the shadow angle. The lamp may have an unusual emission pattern.


Appendix 3: About Footcandles, Lux, Candlepower, Candelas, and Lumens

candelas and lumens Here is the explanation of these units of measure:

COMPARING UNITS FOR MEASURING LIGHT
VALUE UNIT ABR QUANTITY MEASURED SYSTEM QUALIFYING FACTS RELATION
Illuminance Footcandle (fc) Light striking a surface US   lm/ft2
Illuminance Lux (lx) Light striking a surface Metric   lm/m2
Luminous intensity Candela (cd) Light emitted in one direction Both Emission in 1-steradian cone lm/sr
Luminous intensity Candle (cd) Same as Candela US Alternate name cd
Luminous intensity Candlepower (cp) Same as Candela US Alternate name cd
Luminous flux Lumen (lm) Total white emission in all directions Both Restricted to white light cd sr
Chrominous flux Chromen (cr) Total color emission in all directions Both Proposed unit for colored light cd sr
Luminous Emittance Footcandle (fc) Light emitted from a surface US Includes surface-reflected light lm/ft2
Luminous Emittance Lux (lx) Light emitted from a surface Metric Includes surface-reflected light lm/m2

Understanding the relationships between these units is essential.



LINKS