Comparing Standard Light Meter Readings versus Seeable Lumens

Seeable Lumens give us a more accurate measurement

of the usable light given off by a light source


Excerpt from book (Light Medicine Of The Future)

“Since light plays such a major role in the stimulation and regulation of the body’s physiological processes, and since color is merely our perception of light of different wavelengths, Isn’t logical that different colors might then create different physiological as well as psychological affects on us?” Jacob Liberman, OD, Ph.D.

 

* Light Meter Lumens (1920’s)

– Standard Light Meter Readings

This is the light seen predominately by the cone receptors in the eye, which sense the yellow light of the photopic spectrum.  This method of light measurement was developed in 1924 and was generally used to measure incandescent lighting.  Even though this type of measurement is inaccurate, it is still widely used in the lighting industry today.

**Seeable Lumens (1990’s)

– Light That The Eye Can See.

A new method of measuring light was developed by Lawrence Berkeley Labs, Berkeley CA in 1992.  Maintenance Engineering uses this new and more accurate method to measure called “Seeable Lumens.” SEEABLE LUMENS measure the full spectrum, which is both photopic (yellow light) seen by the cones, and scotopic (blue light) seen by the rods of the eye.


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[ME Xtrabrite & XB Vitalux F32T8 linear fluorescent tube lights]


Light Meter Lumens vs Seeable Lumens by Product Type & ME-DTC Color Codes

Maintenance Engineering measures Seeable Lumens from entire spectrum, which is the full spectrum as seen by eye.
"PRODUCT CATAGORY"
- BULB TYPE/CODE
KELVIN/COLOR
TEMP
CRILIGHT METER*
LUMENS
SEEABLE**
LUMENS
COMPAREME-DTC
COLOR NAME
"INCANDESCENT"
- 60W INCAND.2700K100^635826N/AN/A
- 75W INCAND.2700K100^8751138N/AN/A
- 100W2700K100^13501948N/AN/A
"HALOGEN PAR"
- 90W3000K100^14201948N/AN/A
"FLUORESCENT"
- T12 AWX86515100K8637006050+ 69%XTRABRITE ALPINEWITE

- T12 AW82515100K8224004039+ 13%ALPINEWITE
- T12 VL91565600K9122003995+ 12%VITALUX
- T12 CW6741 (EC)4100K75265035790% (Baseline)Spectra-COLWITE
- T12 HG5430 (EC)3000K5427502750- 23%HEARTH-GLO
- T8 AWX85505000K8529504713+ 42%XTRABRITE ALPINEWITE
- T8 VLX91555500K9130505237+ 57%XTRABRITE VITALUX
- T8 VL94545400K9420503711+ 11%VITALUX
- T8 CW75414100K7528504055+22%Spectra-COLWITE
- T8 SR75353500K7528503576+7%Spectra-SUNRISE
- T8 HG75303000K75285033300% (baseline)HEARTH-GLO
"COMPACT FLUORESCENTS"
"QUAD, TWIN"
- 13W AWX85505000K858551375+61%XTRABRITE ALPINEWITE
- 13W CW85414100K858001139+34%Spectra-COLWITE
- 13W SR85353500K858001031+21%Spectra-SUNRISE
- 13W HG85272700K858008520% (baseline)HEARTH-GLO
"SPIRAL CFL's"
- 13W AWX86505000K868001293+50%XTRABRITE ALPINEWITE
- 13W HG82272700K828008520% (baseline)HEARTH-GLO
- 26W AW90505000K9017502945+50%ALPINEWITE
- 26W HG82272700K82175019650% (baseline)HEARTH-GLO
- 40W AW90505000K9024004032N/AALPINEWITE

For 8′ lamps – Approximately double 4′ lumen output.

^ While these lamps are rated at 100 CRI remember this measurement is at a low Kelvin temperature.  These lamps give off light primarily in the yellow and orange spectrum with low seeable lumens.