Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

How do YOU see 405nm?

Grix

0
Joined
Dec 9, 2008
Messages
2,190
Points
63
As you probably know near-UV light is often playing tricks on our brain and everyone perceive 405nm differently, both in brightness and color.
So I'm wondering how YOU would describe 405nm?

The reason I'm asking is because in my experience 405nm is different from what most other people would tell me.
First of all, I see 405nm as more blue than violet, definitely. Also it's a very dirty and bleach color to me, compared to any other wavelength I've seen. The beam is also different from the dot in both color and brightness. The dot is much more "dirty and bleach" than the beam, and much weaker.
Of course the color can't be displayed correctly at a computer screen, but I've tried to draw what I mean to make it clearer to you:
 

Attachments

  • 405nm.png
    405nm.png
    3.6 KB · Views: 981
Last edited:





Joined
Dec 29, 2009
Messages
3,136
Points
63
dot looks the same color as the beam on mine if I shine it at a non-fluorescing surface. I always get a much deeper violet halo around the dot, though. Only way I can tell if I'm focusing it is by looking at the size of the laser "speckle." The larger the speckle chunks, the more focused the dot is.
 
Joined
Jan 15, 2008
Messages
3,575
Points
0
at first i saw no difference between 445nm and 405nm..then now 405nm did appear much more violet...but that was over a year ago since i last seen 405nm.
 
Joined
Jan 12, 2008
Messages
3,290
Points
83
The dot looks truly violet, the beam looks gray-ish in normal conditions. In thick fog the beam looks violet just like the dot.
 
Joined
Apr 28, 2010
Messages
174
Points
0
I'm not sure if people really SEE the colour differently or if it's a matter of subjective assessment of the colour, which has got to do with your experience looking at and describing colours. I mean, the wavelength of the light is a constant, the chemistry of the pigments in the cone cells in your retina are constant between people (unless you have a condition like colour blindness). The processing of the signals from the retina is where it gets tricky - science doesn't understand what goes on here in the realm of the brain to create the perception of colour. However, we do know that people agree on hues formed by mixing this colour with that producing a third wavelength by interference. If your perception of blue was different to mine wouldn't you disagree with my perception of magenta when that blue was mixed with red? We're all human, we all share essentially the same genes for the organs responsible for colour vision, so why shouldn't we share the same perception? Having said that, if someone tells you your whole life, that colour is called blue, and someone tells me it's called violet, then I'll call it violet and you'll call it blue. What do people think?
 
Joined
Nov 17, 2009
Messages
2,031
Points
83
Compared to 445,458 and 473 - 405 is definitely violet and not even "bluish" in my estmation. Though the dot graphic you have there probably doesn't give a good comparison -- monitor calibration varies A LOT, and it varies even more in the blue and violet range...

An odd thing to mention in re jupiter8's comment: there are cultures and languages that use the same word for blue and green, and do not differentiate them.
 
Joined
Oct 24, 2008
Messages
1,057
Points
48
I see it as purely violet, by my mental definition of blue and violet. I see 445nm as a very deep and rich blue. The dot itself looks 100% blue, like a blue LED. But around the dot of 445nm I see this violet-ish haze. When I compare it to 473nm it looks a deeper blue but still not violet. It's hard to describe.

-Tony
 
Joined
Mar 17, 2010
Messages
217
Points
0
To me the beam of 405nm looks like this:
2.jpg

I couldn't decide what color to compare the dot to, but there is a violet haze around it.
 

Razako

0
Joined
Mar 17, 2006
Messages
4,301
Points
113
The beam of a lower powered 405nm looks sort of grayish. With higher powers or fog it looks purple. The spot itself looks pure violet.

The spot of a 445nm looks deep blue and the beam is deep blue with a hint of purple.
 
Joined
Jun 13, 2007
Messages
5,410
Points
113
The beam of a lower powered 405nm looks sort of grayish. With higher powers or fog it looks purple. The spot itself looks pure violet.

The spot of a 445nm looks deep blue and the beam is deep blue with a hint of purple.
Exactly how I see it.
 
Joined
Nov 7, 2008
Messages
5,725
Points
0
To me, the actual spot of a high-powered 405nm laser held stationary looks almost white, with a hint of purple. I attribute that to the fact that my eye is being overloaded with light where the intensity is highest. Surrounding the whitish-purple is very deep violet. The beam in fog looks very deeply violet..
 
Joined
Oct 24, 2008
Messages
1,057
Points
48
To me, the actual spot of a high-powered 405nm laser held stationary looks almost white, with a hint of purple. I attribute that to the fact that my eye is being overloaded with light where the intensity is highest. Surrounding the whitish-purple is very deep violet. The beam in fog looks very deeply violet..

That's what happens to me with 445nm. The dot itself "appears" of a higher wavelength than 445nm because of how our eye interprets the high intensity. Without a lens it looks like a much deeper, and slightly violet, blue.

-Tony
 

rockz

0
Joined
Jan 14, 2010
Messages
84
Points
0
To me it looks violet around the dot, but the dot itself is white. Since I only got my 405nm yesterday, I always try to squint at the dot to try to make it less fuzzy, but it never works.
The coolest thing I've found are these UV blocking lab goggles, and the lens is actually clear, not tinted like safety goggles, so i can focus it and see the actual purple without the fuzz.
 
Joined
Oct 8, 2008
Messages
245
Points
0
its too hard to say, i know its not likely due to evolution and how the rods and cones react mostly the same on all human beings, but can you prove me wrong if i say that what you see as blue and call blue i actually see as your red, but still call it blue because thats what ive been told it is as a kid when people pointed at it and named it. (i am exaggerating)

but i do think it might vary like that slightly for wavelengths, specially at the ends of our visible spectrum. plus putting a picture up on the screen doesn't work either because everyones monitor is set up differently
 
Joined
Feb 15, 2010
Messages
102
Points
18
^ lol @ your exaggeration. Pretty much everything you said was already said above.

405nm looks solid purple to me, especially the beam, which looks a very nice deep purple.
 

Lumify

0
Joined
May 13, 2010
Messages
129
Points
18
When I look at a truly violet light, I see an incredibly bright color that I don't think many people see. The color I see is never even vaguely emulated by a computer screen or polychromatic light. It is a completely separate color from all of the others I see. People always think I'm crazy when I describe this to them because apparently most people see it as purple.

My brother describes the dot of a 405 laser as being "digital". I can't really see what he means, but everyone sees it differently.
 




Top