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The color of 410-440nm range

Exerd

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No one should have to ask if there is a difference between seeing two different wavelengths in the visible region--common sense should dictate that. I won't look down upon any question which inspires further thought and generates better discussion, however. ;)

To add even more confusion to this discussion;

My eyes from left to right differ in wavelength perception during (miopic) night vision--sometimes far more than others. However this only happens in dim conditions, and it seems to me that it occurs more highly toward the red spectrum. I.E., the color temp of white dim light may appear to be 3900k in my right eye, closing the right and then opening the left the light may appear to be 4100k. What's interesting is that this effect goes and comes and I believe has to do with initial night vision only. If I wake up 2 hours later they will have very similar perception. It's not that I am trying to tell others that everyone has this condition between eyes (some won't even realize it), but it made me think about how eyes perceive the end spectrum colors between each other. I have found it necessary to ask descriptive questions to others while viewing the same event. I really do feel that PC monitors and cell phone screens are presenting so much variance between individuals that when one attempts to describe something by pointing to a color reference, they are using a method which is highly unreliable to begin with due to lack of true standardization between device color rendering. Look at your color settings under your display within your cell phone, I have a "vivid colors" mode that comes turned ON by default. It doesn't do great things for color perception equalization, one can imagine.

To the contrary idea that there may be eyes out there which vary more than others as to specific wavelength perceived, what I find from other individuals' input when asked about brightness levels while viewing the same event is remarkably close. In fact when I see a "power graph" online that tells me 520nm is for example, 20-40x brighter than 465nm when perceived by human eyes at the same power level, I almost shout "pooey!". A part of me has attempted to find this connection that I don't see in such power graphs at night, and I find that the relative power graphs actually work out far more closely to realistic within the daytime and among broad sunshine when speaking as to the dot on a building or sidewalk. At night, I expect to have a good mixture of day/night visions as I am not in completely black conditions for miopic vision to take hold. It is under these conditions that others describe similar events extremely similar to how I myself perceive them, and for example a 405nm at 800mW doesn't appear to be 1/100th of a 520nm 1W beam in brightness. Ideally, I would compare them as two equal powers in a true experiment. Noting the recollection of an event at those recited power levels as previous respect, the balance therefore is weighted against my claim. In fact there may only be one order of magnitude which I see in their difference, and by all means I am not so sure that to say an order of magnitude describes the event properly. In terms of how I attempt to perceive and relay what I perceive, I find that I focus on the peripheral pull or contrast of the beam respective to all relative vision.

How likely am I not to notice the beam when it lies in peripheral areas of my vision?

That is a question I ask myself when trying to answer the question of intensity amidst beam colors. The very nature of beams versus dots is a topic into its own right, as then we start to think of atmospheric composition as well as photoluminescence due to quantum energy states of individual photons in various wavelength regions contributing to secondary effects. The mind reels at the amount of variables which could be involved when calculating such events precisely. However, as well-meaning averages go, I find it often necessary to rely on basic descriptions given from others as to their own accounts on the matter. :)
 
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Benm

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Basically it depends on the person, but if you look at the average you can tell things about it:

At equal power, 405 nm looks dimmer than 445 nm.
405 nm also looks more violet/purple while 445 nm is described as 'blue' by most people.

To me both are true, i can definitely see the color difference as well as relative brightness between those wavelengths.

Essentially this problem is similar to how red lasers look to people, comparing for example 650 to 635 nm.

Some people see 635 as a 'bit more orange', some people do not. Personally i see it as a lot brighter at equal power level, but they're both red to me. Side by side i can pick which one is 635, but having a much more powerful 650 could throw me off.
 

Exerd

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Basically it depends on the person, but if you look at the average you can tell things about it:

At equal power, 405 nm looks dimmer than 445 nm.
405 nm also looks more violet/purple while 445 nm is described as 'blue' by most people.

To me both are true, i can definitely see the color difference as well as relative brightness between those wavelengths.

Essentially this problem is similar to how red lasers look to people, comparing for example 650 to 635 nm.

Some people see 635 as a 'bit more orange', some people do not. Personally i see it as a lot brighter at equal power level, but they're both red to me. Side by side i can pick which one is 635, but having a much more powerful 650 could throw me off.

I maybe wandered outside of the topic discussion a bit in that I was attempting to compare a broader region of colors such as 405nm to 520nm, or etc. There are two questions that I find generate different results or different consequential handicaps that are often assumed of end-spectrum color regions such as the handicap UV would have against a central-spectrum color such as green. I find that handicap to be less for the 405nm when it is beams being compared and not dots during daylight. Those two questions are as follows:

How much brighter is a dot during daylight of [color1] vs [color2]?

How much brighter is a beam at night of [color1] vs [color2]?

405nm laser light is often produced from a single-mode laser diode and as such has a very concentrated beam. I do not contest that the beam concentration scales well into perceived contrast ratio, but instincts would tell me that it plays a role in the perception element to some degree. This is an interesting thing to look at because while one beam such as a multi-mode 44Xnm diverges wildly at some arbitrary distance it would also mean the single-mode concentration of light could pull beam visibility figures back towards equality between colors of different relative intensity.

If you just want to know what I think would look "neat" then I would say that a 412-415nm single mode beam would be very interesting to see at power levels >500mW. Whether such a wavelength is possible to produce from a known composition on Earth and within a diode is unknown to me.

I believe 405nm is possible within a diode because of gallium nitride. In theory there should be a way to immediately look at the available elements and determine which wavelengths could be manufactured and which colors do not agree with the physical laws permitting their existence. By determining photon energy levels and the excitation states of electrons in various molecules one would be given the code of possible wavelengths out there, arriving straight from the possible decay energy contributions from the lasing molecules themselves.
 

Encap

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I think some of the confusion.questions are cause by many people using "Wavelength" and "Color" interchangeably, when in fact they are apples and oranges different.

Wavelength is a physical property. The properties of 'Light" are very different from the properties of the human visual system and are independent of it.
See: Properties of Light | PVEducation and here: https://en.wikipedia.org/wiki/Photon

Color is not a physical property; it is merely the brain’s interpretation of different wavelengths of light based on input signal from the eyes.
See: https://en.wikipedia.org/wiki/Visual_system
 
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paul1598419

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That's a good point Encap. One is totally subjective while the other is totally an experimental measurement and does not change from one person to the next. I don't know why people seem to think they are the same, but they aren't.
 
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