Sticky for Neutral White flashlights possible?

bykfixer

bykfixer

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It really boils down to what your eyeballs perceive AZ.

Will there ever be a sticky for neutral tints?
Hmmmmm
 
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A

aznsx

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It really boils down to what your eyeballs perceive AZ.

YES! PRECISELY! That was in fact the primary basis for the unusual approach that I took, and you nailed it.

Test equipment is my life, but it is very linear and precise, and can measure and characterize almost anything including a whole world of things we can't even see. That's great when analyzing the light source, but that's ONLY the signal source. It then has to get through the medium (air), reflected from the target, and then (most importantly) detected by the human vision 'equipment', then processed by the image processing mechanisms of the human brain. As we know from Kruithof, Purkinjie, and the other brainiacs, the human part of this end-to-end system / process / application is anything but linear (or frankly even predictable). Rather than fixating on the signal source, it's only at the destination (where the primary objective / end user and beneficiary of this application and the reason for having a flashlight in the first place) evaluates the resulting 'image' provided by that human optical system (including the image processing), and the image they perceive is ALL that matters here.

AKAIK, that entire human part of the application is not replicated or emulated precisely by any known test system / equipment, so that's why I'm using the only test equipment I know of that is capable of doing that evaluation. Me.

Makes no sense to expend endless effort analyzing the signal source, then presuming to be able to predict what image the human will be presented with after that light is bounced off an object. I don't think such an algorithm exists, and I think anyone who claims to be able to do that is likely trying to fool someone!

EDIT: BTW, what I'm referring to here is only half of what I did 'differently' - but the rest is for another day / another post.

EDIT2: You also mentioned something else very important in one of your posts when you referred to illuminating your faded pickup with a light, but found that it was being rendered 'new fire engine' red. You didn't reference a random object you aren't so familiar with, nor were you referencing how the truck looked using a different flashlight. You knew exactly how that truck actually looked based on a composite image in your brain of that truck based on seeing it over time and in many different lighting situations, and your brain told you that what you were seeing was not accurate. That, in essence, is the other critical part of the approach I took, only using more complex and subtle targets and coloration.
 
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bykfixer

bykfixer

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One early morning I went to get dressed using a neutral tint (4500k), high cri flashlight and a t-shirt I knew was a gray with a slight hint of green appeared brown. I tried out a cool white 6200k) light and "phew, thank goodness" it appeared normal again.
Now the neutral, high cri light probably got the color a lot closer to correct than one with a lot less accuracy, but the red/yellow bias of the neutral beam persuaded my eyes I was looking at a brown object.

One thing people may not remember about old incan house hold light bulbs was that most of the globes were frosted white in order to present a cooler beam than those with clear globes. Hence the illusion of a cool white beam.
 
A

aznsx

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<<I do not have the FULL specification of the specific LED(s) used in my human testing, but they were simply identified by the flashlight distributor who provided them as (as I recall): SST-20 R9080 4000K. They may or may not have the full specification / part number for those devices.>>

Just in the interest of complete accuracy, the exact description I have of the emitters I used in my evaluation, as provided by the flashlight distributor is actually (since I don't fully understand these things, I need to quote verbatim:):

Luminus SST-20 R9 CRI-95 4000K Neutral
 
T

twistedraven

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One early morning I went to get dressed using a neutral tint (4500k), high cri flashlight and a t-shirt I knew was a gray with a slight hint of green appeared brown. I tried out a cool white 6200k) light and "phew, thank goodness" it appeared normal again.
Now the neutral, high cri light probably got the color a lot closer to correct than one with a lot less accuracy, but the red/yellow bias of the neutral beam persuaded my eyes I was looking at a brown object.

One thing people may not remember about old incan house hold light bulbs was that most of the globes were frosted white in order to present a cooler beam than those with clear globes. Hence the illusion of a cool white beam.

Frosted white bulbs do not make the color temperature cooler; they merely diffuse the beam more than a clear bulb. Some bulbs were blue glass however in an attempt to make the light cooler.
 
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twistedraven

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Pure white is completely neutral, allows all wavelengths of light through in equal amounts, and does not affect the spectral balance of the light. Frosting the inside of the bulb effectively cuts down on glare and harshness when close to the light by diffusing it, and also makes the glass stronger.

Daylight incandescents use varying degrees of blue coatings over the glass to effectively neutralize the spectral balance of the light output, allowing less of the warm yellows and reds to pass through, but allowing more of the blues and greens to pass through. As a result you can get incandescents that have color temperatures up to 5000k.
 

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