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Why are red dots red?

Discussion in 'General Gun Discussions' started by Frye, Jun 24, 2013.

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  1. Frye

    Frye Member

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    Just curious as to why Aimpoint and EOTech optics are always 'red dots'. For comparison if a green laser is much more visible compared to a red laser based on the way our eyes perceive color, why don't they have Green Dots sights?

    I know there's some cheap red dots that allow you to change the colors but that always seemed more like a gimmick than a feature.
     
  2. Bovice

    Bovice Member

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    Red has the largest wavelength, it's been awhile since I studied optics but I think it has to do with being easier to see in all lighting conditions/from a distance.
     
  3. firesky101

    firesky101 Member

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    I have also heard battery life is significantly greater with red.
     
  4. Bianchi?

    Bianchi? Member

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    High contrast on target. Red isn't a very prevalent color in nature, and shows up clearly against green and brown.
     
  5. Deus Machina

    Deus Machina Member

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    Also, originally it was because of the available technology and materials.
    Those $5 laser pointers? All red. Back when they were $100? Also red.
    It's because the red laser was the only visible one they could make at a reasonable price at the time.
    Now, I'm sure it comes down to price (they're still the cheapest), contrast, and because that's just what they've always done.
     
  6. JustinJ

    JustinJ Member

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    Other colors in lasers also tend to be less energy efficient and thus less battery life.
     
  7. Bartholomew Roberts

    Bartholomew Roberts Moderator Emeritus

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    Contrast is important for being able to aim and acquire a target quickly. Red offers contrast with a wide, wide range of targets. Some of the newer green reticles do a suprisingly good job of contrast while also being eye catching; but they tend to be more expensive to do right (though I don't know why that is).

    Look at the TA01NSN reticle as a great example. Because the powers that be had determined the human eye picks up amber better than other colors, they made the reticle amber; but on a planet lit by an amber sun with a lot of browns, tans, and yellows, the reticle (illuminated only by tritium) would sometimes illuminate just brightly enough to wash out the reticle completely against the background - especially at dawn or dusk.
     
  8. Reloadron
    • Contributing Member

    Reloadron Member

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    I believe Deus Machina pretty much nailed it as well as others. Red LASER diodes are cheap, real cheap with their cost dropping like a rock over the years. Give this link a read. I believe it covers it well. Also yes, battery life is also a key player in the equation.

    Ron
     
  9. Rule3

    Rule3 Member

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    For someone with red green color blindness ( not completely but enough to fail a test) their choice of colors suks:D I can seen green dot optics much better. Red is invisible to me during the daylight. I vote for orange or bright yellow.:)

    I have fiber optic sites on some handguns, red might as well be black but the green really glows in the sunlight.
     
  10. 22-rimfire

    22-rimfire Member

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    Color blindness.... that is an interesting addition to the discussion. Many people are slightly blue-green color blind but full color blindness is not common where everything is shades of grey.
     
  11. Queen_of_Thunder

    Queen_of_Thunder member

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    Ok I'll play this game. Why are red dots red? Because if they were blue they would be blue dots.
     
  12. hso

    hso Moderator Staff Member

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    Deus Machina is correct.

    After the ruby laser and the gallium-arsenide laser, the red diode laser was the first "inexpensive" laser diode (and stayed so).
     
  13. JohnBT

    JohnBT Member

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    "Many people are slightly blue-green color blind"

    99% of all colorblind/colordeficient people have red-green color deficiency.

    Iirc, an article in American Rifleman said that the green lasers were 10x more expensive than the red.
     
  14. aarondhgraham

    aarondhgraham Member

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  15. Willie Sutton

    Willie Sutton Member

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    Should I point out that a minority of "red-dot type sights" use a laser as opposed to a LED? Your cheap <fill in the brand name> multi-color "dot" is not using a laser.


    Willie


    .
     
  16. ljnowell

    ljnowell Member

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    They do have green dot sights. I use one every tuesday in my bullseye league.
     
  17. JustinJ

    JustinJ Member

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    I believe that is because it is not a holographic site which uses a laser. To my knowledge red and green are the only practical options for holographic sights with laser diodes. The latter being harder to implement due to size and energy requirements. In fact, green laser diodes don't actually exist but instead an IR laser must be converted to green. The article below explains this well:

    http://www.americanrifleman.org/articles/going-green-with-lasers/
     
  18. brickeyee

    brickeyee Member

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    Green uses an IR laser that is then frequency doubled up into the visible spectrum at green.

    It is a lot more complicated, and uses a lot more power for the same optical output power (though the human eye is generally a lot more sensitive to green).

    The 'color change' is not 100% efficient.
    Unless filtered, there is still a bunch of IR coming out.
     
    Last edited: Jun 25, 2013
  19. Frye

    Frye Member

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    All excellent points. Thanks for the explanations.

    I just ordered an Aimpoint PRO and it just kinda made me wonder why they are mostly always 'red dots'.

    On that note, does the Aimpoint use and LED or a laser as some have mentioned? Is it just EOTech that uses a laser?

    The point of contrast is excellent. Red is opposite of green on the color wheel so ergo it's hypothetically the best for pickin up against a green (forest) backdrop. Though it would seem those over in the sandbox would get a lot of benefit from a purple reticle according to that logic.

    It would be interesting if future optics could automatically adjust brightness, color, & whatever else you may need to suit your environment. And then it's always a matter of personal oppinion which is best so it could make the whole argument subjective.
     
  20. JustinJ

    JustinJ Member

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    According to their site, they use an LED rather than a laser diode. I guess that makes sense given their battery life. In that case i would expect they should be able to make other colors easily.
     
  21. mac66

    mac66 Member

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    I have a cheap dot sight that has red, green and blue dots. IMO the red is easier to see and I prefer it.
     
  22. ThePenguinKnight

    ThePenguinKnight Member

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    Are there any dot sights (of any color) that use a real laser diode instead of an LED?
     
  23. GrOuNd_ZeRo

    GrOuNd_ZeRo Member

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    I was always under the impression regular Light Emitting Diodes (LEDs) were used oposed to Laser diodes, lasers seem harmful to eyesight IMO but I could be wrong since they are reflected rather than directly aimed at the eye.

    Amber is used in many tritium sights in the military such as gunner's sights (Howitzers/Tanks) and green in Heads-Up Displays (HUDs) in aircraft.
     
  24. JustinJ

    JustinJ Member

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    I know my eotechs had warning labels about laser radiation. Also: http://www.eotech-inc.com/making-a-hologram
     
  25. Deus Machina

    Deus Machina Member

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    The cheaper ones may use LED's and you're only seeing a reflection of the spot of light.
    More expensive ones use an actual laser, which makes for a more directed, clearer dot.
     
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