Vancouverite -
My opinion is in agreement with _js_ in that it is both. Individual perception is large part of it too. For me a 4 cell mag overdriving a 3 cell Radio Shack XPR 103 in candle mode is nicer than an LED in candle mode. Yet, LEDs are advancing so quickly, not just in power but color rendition, it would be no surprise if very soon one where developed that would be pleasant to my eyes as a lantern.
I've posted the following before. I thought you might find it to be of some interest:
This post is broken up into five parts.
The Introduction
The Mildly entertaining, somewhat annoying "test"
The Opinionated Commentary
The Incomplete yet genuine, good faith attempt at an intellectually respectful revelation
The Question for the basis of discussion
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Introduction
Possibly the most important component of our flashlights and torches is the actual light that is thrust out of them. What that light does to illuminate its objective target in the way of returning an image to us is important enough to be the basis of many of our discussions. One of my favorite subjects to learn about is light itself. What creates it, how it acts and reacts, its intensity, its power and how it is defined are aspects of light that fascinate. Of great interest to me is the spectral components of a beam of light. The different frequencies or colors present in different light beam emissions can greatly effect the imagery or information returned to the user.
Here is a mildly entertaining, somewhat annoying "test". The answers are provided for ease of reading.
1) Environment: Fair to poor office lighting.
Would light from a blue LED peaking near 470 nm help or hinder in reading small print?
Answer:
It depends on the individual. Some people report that it blurs the print and hurts their eyes, some report there is not much difference, still others report a significant increase in their ability to read small print. One legally blind individual reported being able to retain their job which required reading small print simply by employing the use of a blue LED torch. He could not perform this function without the aid of blue Inova even with powerful glasses.
2) Environment: Low ambient lighting during a stage presentation such as a play.
Would light from red LEDs peaking near 625 nm spotting the target character help or hinder in defining the image of the target character?
Answer:
It depends on the individual. Some members of the audience will experience little effect in definition; others will notice a slight blurring; still others will notice some increase in definition. What most audience members will notice is a different definition rendition as well as a different depth rendition in comparison to everything else on the stage. These two differences highlight the target character and set that target character apart almost as much the obvious difference of the red color.
One individual reported that they were so visually impaired that they could barely navigate in low ambient light situations without the use of both a powerful blue light and a powerful red light used simultaneously. They designed and used a head mounted dual LED device to successfully satisfy this need.
3) Environment: Woods/Forest at night, clear sky, away from population and no moon.
Would light from a cyan LED peaking near 505 nm help or hinder vision in the area of defining the target image?
Answer:
It depends on the individual. Some individuals report that they lose so much color rendition that they feel almost bewildered. Others report a preference for cyan in this environment due to its definition of target capability as well as its particular color rendition capability. With effort, individuals can train their eyes/vision processing to take advantage of the aspects some wavelengths afford.
4) Environment: Woods/Forest at night, clear sky, away from population and no moon.
Would light from a royal blue LED peaking near 455 nm help or hinder vision in the area of defining the target image?
Answer:
It depends on the individual. Some individuals report a blurring effect; others nothing; others reported that it was pretty. One individual reported that he could read distant signs he could not possibly read without royal blue light returning the image. Other individuals substantiated this report with their own real world investigations.
5) Environment: Jewelry store, low to no lighting.
Which frequency of light is best for causing diamonds to fluoresce?
Answer:
380 nm. 395nm will work also. However not all diamonds fluoresce. Some diamonds fluoresce different colors. If a yellowish diamond fluoresces blue, the effect could be strong enough to mask the yellowish tint when viewed in a jewelry store's fluorescent lighting. You might be surprised by the diamond's true color when you look at it at home under different lighting. The reverse is true for diamonds that fluoresce yellow. They can appear more white under incandescent lights, but acquire a yellowish tint in ultraviolet light. A strong yellow fluorescence bring diamond prices down, sometimes quite a bit, since yellowish tinted diamonds are generally less desirable than whiter stones. A blue fluorescence can help increase the prices of diamonds with yellowish tones.
6) Environment: Low ambient lighting during a stage presentation such as a play.
Which of these colors of light would be easiest to hide from the audience on non-target backgrounds; blue 470 nm, red 625 nm, cyan 505 nm or royal blue 455 nm?
Answer:
blue 470 nm.
7) Environment: Medical diagnosis.
Which color of light would be best for diagnosing subdermal vascular anomalies; blue 470 nm, red 625 nm, cyan 505 nm or royal blue 455 nm?
Answer:
red 625 nm. One specific instance is where 625nm/660nm is used in oximetry. 910nm IR is used in tandem in oximeters for attaining a ratio of absorption differential between the two (red and infrared) frequencies.
8) Environment: Woods/Forest at night, clear sky, away from population and no moon.
What color of light is best for tracking blood?
Answer:
The discussion continues among folks all over the world in many different venues. Some individuals report blue works for it's absorption properties. Some individuals report that red works for its reflective properties. Some individuals report that a strong warm/white LED works very well while still others report that incandescent light is best for them.
9) Environment: World.
Which personal lighting tool is better for rendering diverse target images; LED or incandescent?
Answer:
It depends on the target and possibly more importantly it is dependent on the individual observer. All perspectives are valid.
Opinionated Commentary
Each individual has unique optical capabilities. Each individual has unique image processing capabilities. For a moment, couple all the above mentioned light frequencies and their different renditions of different targets with the fact that individuals see images differently. All those colors. All those targets. All those eyeballs. All those brains. One would think it would be a simple logical step forward to accept that one type of light is better for one person's interpretation of a target image and a different type of light is better for another person's interpretation of a target image. My observations indicate to me that it is in fact not such an easy logical step.
I think I may know why. It has to do with what is right before your eyes. We instinctively trust our vision for survival. What we see must be correct because we are seeing it. Now that might be considered to be empirical evidence. Add to that varying degrees of knowledge of light. From here the individual might submit that what works for them does so because of scientific fact. Since the preference is evidenced empirically and is supported by scientific fact, the preference might be considered to be an absolute. It's not.
This is the complicated part of the pot of ingredients that can produce enthusiastic discussions and sometimes those discussions can cook up to produce quite a spicy dish of conversational fare.
And there's more. One very interesting fellow has let me know (and I now agree with him) that people can train their eyes to use different types of light to enhance the information they receive from an image. Further he contends and I agree, that individuals can train their light processing capabilities and can even recalibrate their processors using different techniques not limited to but including simple concentration.
These words I'm using to attempt to make a point may or may not be of use. Let's try another question. Is a blue LED the best choice for reading a map? Why, of course not. The best light for reading a map would be incandescent. No wait. The best light would be warmish white LED outputting exactly 128 lux. Maybe not. Remember that legally blind fellow who's job depended on his ability to read small text and this task could only be accomplished by enhancing the target with a blue Inova? He doesn't care what color the interstate is. He just wants to know where I-40 West is. Now if he and I were in a "save the world" scenario and he was the guy that had to cut the correct wire on the bomb before the timer reached zero, I might be inclined to hand him an incandescent light for its color rendition capability. A better choice for me, if time allowed, would be to ask him which light he would prefer for the task at hand. In this case his opinion makes a world of difference to me.
Like many, I have certain lighting preferences for different tasks.
While night fishing I prefer to use a tiny LED torch to tie lures, a no-spill TIR LED torch to spot the fish the guy twenty feet from me just pulled on shore and a powerful incan torch to see if that's a small branch or large snake floating in the water. Not everyone will prefer my choices. Individuals see images differently and process those images differently. If a fellow tells me he has no problem identifying an un-moving, mostly submerged cotton-mouth water moccasin at 30 feet out using an LED flashlight I'm inclined to believe his choice is best for him despite my own personal empirical evidence or my somewhat limited grasp of the science of light.
Incomplete yet genuine, good faith attempt at an intellectually respectful revelation
a. The little "test" has an obvious, albeit poorly constructed, thread of logic that hopes to deliver an acceptable conclusion.
b. I want you to agree with me.
c.
Question for the basis of discussion
Is it possible that in a given environment and while targeting a given object, that one type of flashlight emitting a particular class of light beam might truly be more useful to some people while a different type of flashlight emitting a different class of light beam might truly be more useful to other people?
Completion of respectful intellectual revelation
c. The intent of the post is to promote more acceptance of the validity of the perspective of each individual member, possibly inspiring more useful and enjoyable discussions about "What type of light is best?"
