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Scotopic lumens data table for various lamps and their definition

3118 Views 0 Replies 1 Participant Last post by  Electric_Light
I came across this in GE Lighting catalog, so I'll leave it here for reference:
This questionable measures are not industry recognized and can not be used to meet specification criteria. So, if specifications call for "security luminaire shall have an efficacy of >75 lumens per watt", you can't just interpret that it'll be used to assist night vision and apply scotopic value to fudge numbers.

Not that its a surprise, but some LED and induction sales department genericize other lamps and refer to the product they sell by the tradename and make it look better. Sorta like our super premium snow tires have much better traction on most favorable 4x4 configuration compared to some generic aged worn snow tires on 2WD.(Ref A, B, C). So that daylight (865) $3 CFL from the Home Depot has the same multiplier as your super premium "induction".

"Scotopic/Photopic (S/P) Ratio:
This measurement accounts for the fact that of the two light sensors
in the retina, rods are more sensitive to blue light (Scotopic vision)
and cones to yellow light (Photopic vision). The Scotopic/Photopic (S/P) Ratio is an attempt to capture the relative strengths of these two
responses. Cooler sources (higher color temperature lamps) tend to have higher values of the S/P Ratio compared to warm sources."

8xx= CRI in 80s
xx = kelvins in hundreds. e.g. 30= 3,000K

830: 1.3
835: 1.5
841: 1.8
850: 2.0
865: 2.3
0.1 to 0.2 points lower for 7xx.

How this table is interpreted is that if a 841 lamp is rated at 1,000 lumens, you would multiply it by the table value to get "scotopic" or night vision weighed lumens, so it would be 1,800 for 841, 2,300 for 865.

A regular filament is said to be around 1.4 and mercury vapor, despite its very high CCT (kelvin), is only 0.8. According to some questionable reference:
http://www.getdeco.com/products/induction/intro/pdf/Photoptic_vs_Scoptopic_Case_Study.pdf


I don't know the validity of it, but how this table works is that
IESNA doesn't endorse the use of this system and neither does GE. It's just there in their catalog for reference and its not an accepted standard in the industry.

http://www.gelighting.com/na/busine...hite_papers/download/photopic_scotopic_lb.pdf

Rods provide peripheral and night vision. Do not respond to red.
Cones cover much smaller viewing angle.

Ref:
http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html#c4




Ref A:
http://www.yjbled.com/scotopicphotopic.php

Ref B: (even Howard Industries is playing this game of convenient deliberate omissions of LEDs real MEAN LUMENS?)
http://www.howard-ind.com/howardlighting/Documents/ProductLiterature/HIDToLEDCrossReference.pdf

Ref C: http://carolinainductionlighting.com/index.php?option=com_content&view=article&id=128&Itemid=208
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