A light producing a Neutral Tint (4500-5000K), with CRI above 90 is considered ideal.Q: I don't care about tint color, I just want brightest?
A: COOL LED are still leading in lumen output over NEUTRAL LED, but not by much anymore.
With today's high output LED - NEUTRAL tint can now be as close as 6-7% of the Lumen output of similar Cool White LED, and human eyes typically can't see less than 30% difference in lumen output.
But, output TINT/Color differences will be very obvious, one being bluish, while other is yellowish. Interestingly - when a user compares two identical flashlight using identical reflectors - one with Cool White LED, and one with Neutral White - our BRAIN says the yellowish NEUTRAL is MUCH dimmer than the bluish COOL... but look again, most users can actually see a lot better and clearer with the NEUTRAL light.
Q: I am color blind - will this make a difference?
A: Absolutely! About 8 percent of males, and 0.5 percent of females, are color blind in some way or another, whether it is one color, or a color combination... this effects how the user "sees" and uses light.
Generally, a color blind user will not see the benefits of the different color tints - and just goes with brighter cool tint regardless of their intended use, or, will use a tint that looks best to them (one of our customers says NEUTRAL looks significantly brighter to him!).
Not sure if you are Color Blind? Here is a quick test... Ishihara Color Test
Interesting BBC News article: Do you See What I see? http://www.bbc.co.uk/news/science-environment-14421303
Can you trust your eyes/Brain? Amazing shade illusion will make you see the light. http://games.yahoo.com/blogs/plugged-in/amazing-shade-illusion-see-light-024226513.html
And another Brain Twister. How Many Black Dots Illusion http://www.iflscience.com/brain/this-12-black-dot-illusion-is-blowing-a-lot-of-minds/
Brightness = LUX, A measure of the intensity of the center spot.
Q: Why is this xxx Lumen Light not as bright as my other xxx Lumen Light?
A: Very subjective, it all depends on how the light output was measured, how the light output is focused, the Color Temperature, and, how YOUR eyes see it...
but let's first define some common terms:
LUMENS, Bulb Lumens/Emitter Lumens/LED Lumens = amount of light being produced and measured at the surface of the LED.
OTF Lumens = amount of light being produced and measured coming Out~The~Front of light (this accounts for loses with reflector and lens, 20-30% loss is typical).
ANSI LUMENS = amount of light being produced, and measured OTF of light after a specified amount of time - usually 2-3 minutes.
(We compare Lumens and OTF/ANSI Lumens, to Automotive Crank/Engine Horsepower and Rear wheel/brake Horsepower)
Throw = how far the beam reaches.
Q. How much LUX do I need?
A. A good observation/baseline provided by our LEO/Military users: "7,500 LUX, allows them to count fingers at 75 meters"!
But note, 2x LUX does not produce 2x throw. LUX to throw generally speaking, has a 2 to 1 ratio (2x LUX, provides approx 50% more throw). Search the internet for "inverse-square law of light", for a full scientific explanation. ;P
Common Misconception: More Lumens makes more throw. No, not necessarily, it is the focus of output, the size of the reflector/head, and, the lumens that creates more throw. (We have several lower lumen lights that outthrow some of the higher lumen ones!)
EX: In the household, a 100w light bulb, vs 100w flood light, vs 100w spot light all create 100 watts of light,
ie. they are all the same lumens of a 100w bulb, but the output beam appearance and use is completely dependent on how the light output is focused (area light, vs flood, vs spot).
With flashlights ~ Lumens only tells you how much light is being produced, not how it is focused, by adding LUX to the equation one can determine what type of output should be expected when compared to another light... EX: more floody vs more throwy etc.
More Info http://flashlightwiki.com/Main_Page
TIP: A quick and easy way for any user to more objectively compare one light to another light without testing equipment is to perform a "ceiling bounce test".
In a darkened room (bedroom, living room, etc) ~ point flashlight up to center of ceiling, while you look down to floor, then switch light ON... look at the amount of light reflected down to the floor, wall, and surrounding area. Do this/compare with another light ~ and you can quickly determine the amount of light being produced with one light vs another light.