Red wavelength comparison (ADD YOURS)

4mW 635nm, 20mW 642nm, 40mW 685nm - on mountain crystal














42mW 685nm, 50mW 650nm, 35mW 638nm

heh, when I saw the topic, I though it's a place's name "mountain crystal" I think it's in the 3rd terminator ? oh wait, or it's crystal peak?

Here is mine, both 5mW:

Hey What is that chrystal thing?

probable just a pice of quartz from switserland , the pics are overexposed it's nothing special

635 is RED, RED, RED, RED, I was hoping it would be orangish but it is totally RED. It is 650-660 that is an odd color, but to me, 635 is like "firetruck" red. Nice, but never the less red.

Still encounter people who say they can't see the difference between 650/660 and 635, though. Seems hard to not notice, to me.

685 is just evil... Almost looks like 5mW of 650 at 40mW...

Everybody's eyes/brains are wired differently. We all have slight variances in our rod & cone cells.

I read somewhere a long time ago - it's been tested and proven in a lab, apparantly; females (generally) have a more refined sense of colors & smells. (generally) they can distinguish between slightly different shades of colors, whereas us guys would just see "red", and they can distinguish between slight variances of odors.

I don't know, I don't have a wide range of experience, but I wouldn't be suprised if some people can't see much or any change between 650/660 to 635, while others can.

JBTexas said:

I read somewhere a long time ago - it's been tested and proven in a lab, apparantly; females (generally) have a more refined sense of colors & smells. (generally) they can distinguish between slightly different shades of colors, whereas us guys would just see "red", and they can distinguish between slight variances of odors.

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I am not aware of this study but I have seen one that found that men use less labels for the same color spectrum.

Men will identify colors like
red
blue
orange
yellow
pink
brown
black
white

Women will identify colors as
rose
fuschia
baby blue
lime green
turquoise
etc etc - I had to stop because I am guilty of not knowing most of these specific colors.
As well as the basic red, blue etc

I dont believe the study talked about perception as much as labeling. Probably a different study though.

Which would be the best wave length of red VISUALLY in your opinion? From 670 to 640nm.

Does anyone have a picture comparing the beams of 635, 650 and 671 beams (like all in the same photo)? I know I've seen pictures on this forum where people have pictures comparing 445 and 473 and a 488 argon I think for blues and a homemade 515 and a 532 for greens. I would like to see how 671 looks compared to 635 and 650 if possible

Helios said:

I am not aware of this study but I have seen one that found that men use less labels for the same color spectrum.

Men will identify colors like
red
blue
orange
yellow
pink
brown
black
white

Women will identify colors as
rose
fuschia
baby blue
lime green
turquoise
etc etc - I had to stop because I am guilty of not knowing most of these specific colors.
As well as the basic red, blue etc

I dont believe the study talked about perception as much as labeling. Probably a different study though.

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I wouldn't use these color names in every day conversation with people but this is how in my head I break down colors.

Primary:
Red
Green
Blue

Secondary:
Cyan
Magenta
Yellow

Tertiary:
Rose (Red + Magenta)
Orange (Red + Yellow)
Chartreuse (Green + Yellow)
Spring Green (Green + Cyan)
Azure (Blue + Cyan)
Violet (Blue + Magenta)


I've never went to a psychologist but I suspect I have some sort of weird OCD type fixation when it comes to colors. I have this weird habit of counting how many different colors something comes in. It's weird.

Most cameras tend to pick up 650 nm and longer waves as pink, and 635 nm as orange. But clearly that's NOT how these two colours look once we look at them with our eyes. The crystals are quartz most likely, maybe you should have used a more interesting crystal like calcite and see what comes out.

This thread raises the issue of Failure of Color Constancy. The image-processing centers of the brain try to keep the colors of objects we see constant even in greatly varying lighting conditions. A green car still looks green, even at sunset when most of the light from the sun is red. However, color constancy only works up to a point. Sometimes it totally fails. The moon is the same color as asphalt pavement, i.e., black, or 10% albedo with very low color saturation, but that's not what it looks like at night.

Color constancy fails for brightly lit objects against a dark background, and for anything that glows, like the embers of a campfire. I think laser dots viewed at night or in a dark room fall into that category.

Even though I haven't found any literature to back this up, I suspect that when color-constancy fails with bright glowing objects, the brighter the object, the more its apparent color will be shifted towards the center of the visual spectrum. That's because relative brightness is one of the clues our brains use to figure out what color something is.

Most people's peak sensitivity for scotopic [correction: photopic] vision (color vision) is 555 nm. For each of the cone-cells separately, peak sensitivity is something like 440nm, 535nm, and 565nm respectively for S-, M-, and L-cones ("blue," "green," and "red").

Also, if anyone could ever figure out how to take photos of laser dots and get accurate color reproduction on a computer screen, they could make a fortune.

zyxwv99 said:

Most people's peak sensitivity for scotopic vision (color vision) is 555 nm.

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That would be FOTOPIC vision, or daylight vision. Scotopic (=night) vision is largely colourblind but has a peak sensitivity around 510 nm

Thanks for the correction. (I was getting photopic and scotopic mixed up.)