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Try this... if you own a 488nm (may work w/ others IDKFS)

hakzaw1

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Saw this a few years ago but forgot about it.
I was trying out a new blue mini lab 60mW 488 nm
see the pic.
anyhoo
While I was running the 488nm I got out a 532 pointer.
with the 488 off- the green looked very 'normal'
BUT in the 'presence' of 488 -- the 532 turned a very yellow yellow-
not by combining -- I was using a lumia glass-- and the 532 made the glass balls yelllow and blue but no more green.. turn off the 488 and the efx are less and soon return to a 'normal' green-- turn the 488 back on-- the 532 becomes very YELLOW--

try it-
& see if you can take a pic of this .. unlikely I am told--coz its our eyes that see 532 as yellow--would not appear that way on a camera..very interesting and nice color p 480 60 mW.jpg
 
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Benm

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It's your eyes and brain doing this, so a camera cannot capture what you are seeing.

The human visual system as a sort of auto-white-balance system, which is useful because you want to see the color or things under different conditions like full sunlight or overcast days. This is an evolutionary thing: if for example some edible fruit looked orange in sunlight but red when overcast, yet another fruit was toxic and looked orange that'd be a bad thing.

This is a fairly well adaptive system, and makes things mostly look the same color under different lighting conditions (i.e. cool white and warm wide, but full spectrum light).

It can get things wrong though, as in this example: it assumes the green is yellow because the blue light shifts the average wavelength down - i.e. a higher average color temperature.

If your only light source is a very narrow monochromatic light you may lose all color perception. One common example of this effect you can experience when the only light source are those good old orange-yellow low pressure sodium street lamps: Everything is in black and white under those, even things that are normally brightly colored like a red t shirt or green leaves. Nowadays it's rare to find places with those lamps as the single source of light, they used to be more common in smaller streets in europe. The LED replacements, and high pressure sodium lamps have broader spectra so you still see some color.

But you can try this: If you have a room that can be made entirely dark (a walk in closet perhaps, or one with no windows) and use a 532 nm laser pointer as the -only- source of light (point it at the ceiling so it reflects from the dot in all directions) you would not be able to see color in that room, at all.

It's not likely to work with any other light source though, even things like led's have a spectrum that is broad enough for your visual system to make some sense of things, although it may make mistakes (i.e. something green appears white etc).
 

Pelagius

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Hey Hakzaw1, I was just noticing how my 465nm changed my perception of my 492 and 505. Not as drastic as yellow-but by itself the 492 looks cyan-with the 465 the 492 looks blue-green. I'll try it with a 532nm.

EDIT: my 532 just looked YELLOW (when I point it next to the spot of the 462 nm).
 
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paul1598419

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I have noticed this a lot since I started measuring new diodes for wavelength. I have many wavelengths that are quite close to each other, but are between 486nm and 492nm. Even these look quite different next to each other and can change my perception of other colors when observed next to one of my many wavelengths. It is all subjective as you can't get a camera to do it. It is fun, though.
 

hakzaw1

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Thanks both of you for the posts..
The shade of yellow w/ 532 and 488 'meet' is beautiful.. and I have no probs with that being 'just' how we/I see it... lots of laser stuff is like that.. seeing yellow made by green and red is not too different & any Lumia or grate will seperate them.. and undo your effort.. but these two only need to be in same room.. now-- want to see what is made when using a dichro mirror and actually combining 488 and 532--(BTW I did a proper edit but my typos (480 instead of 488) but one could not be edited. in the text ..yes -in the title -----no-- where is the 'Go Advance' that allowed title editing-- ???
Some new members have been advised about improving the title in their (very important) intro... but how is that done now?? duh
(MY title improvement is just adding your location to catch the eye of more members living nearby.) gave up on that...
 




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